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23  WEST  MAIN  STREET 

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CIHM/ICMH 

Microfiche 

Series. 


CIHIVI/ICMH 
Collection  de 
microfiches. 


Canadian  Institute  for  Historical  Microreproductions 


Institut  Canadian  de  microreproductions  historiques 


1980 


Technical  and  Bibliographic  Notes/Notes  techniques  et  bibliographiques 


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L'Insti    .t  a  microfilm^  le  meilleur  exernplaire 
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modification  dans  la  mSthode  normale  de  filmage 
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Coloured  covers/ 
Couverture  de  couleur 


n 


Coloured  pages/ 
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D 


Covers  damaged/ 
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□ 


Pages  damaged/ 
Pages  endommag^es 


D 


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Couverture  restaurde  et/ou  pellicul^e 


n 


Pages  restored  and/or  laminated/ 
Pages  restaur^es  et/ou  pellicul^es 


n 


Cover  title  missing/ 

Le  titru  de  couverture  manque 


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D 


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D 
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D 


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Ce  document  est  film6  au  taux  de  reduction  indiqud  ci-dessous. 

10X  14X  18X  22X 


y 


26X 


30X 


12X 


16X 


20X 


24X 


28X 


32X 


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The  last  recorded  frame  on  each  microfiche 
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whichever  applies. 


Les  exemplaires  originaux  dont  la  couverture  en 
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empreinte. 

Un  des  symboles  suivants  apparaitra  sur  la 
dernidre  image  de  cheque  microfiche,  selon  le 
cas:  le  symbole  — ♦■  signifie  "A  SUIVRE",  le 
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Lorsque  le  document  est  trop  grand  pour  gtre 
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et  de  haut  en  bas,  en  prenant  le  nombre 
d'images  ni&cessaire.  Les  diagrammes  suivants 
illustrent  la  mdthode. 


1 

2 

3 

32X 


1  2  3 

4  5  6 


BY  THE   SAME  AUTHOR. 


CHEMICAL  AND  GEOLOGICAL  ESSAYS. - 
with  a  New  Preface  ;  pp.  xlvi.  and  4S9 ;  8vo. 


•Second  Revised  Edition, 


MINERAL    PHYSIOLOGY   AND    PHYSIOGRAPHY;   With  a  Gen- 
eral Introduction,  —  pp.  xvii.  and  710. 

Contents.  —  Preface;  I.,  Nature  in  Thought  and  Language;  II., 
The  Order  of  the  Natural  Sciences;  III.,  Chemical  and  Geological  Relations 
of  the  Atmosphere;  IV.,  Celestial  Chemistry  from  the  Time  of  Newton; 
v.,  The  Origin  of  Crystalline  Rocks;  VI.,  The  Genetic  History  of  Crystal- 
line Rocks;;  VII.,  The  Decay  of  Crystalline  Rocks;  VIII.,  A  Natural 
System  in  Mineralogy,  with  a  Classification  of  Silicates;  IX.,  History  of 
Pre-Canibrlan  Rocks  ;  X.,  The  Geological  History  of  Serpentine,  with  Studies 
of  Pre-Cambrian  Rocks ;  XI.,  The  Taconic  Question  in  Geology ;  Appendix; 
and  Index. 

IN   PREPARATION: 

MINERALOGY    ACCORDING   TO   A    NATURAL    SYSTEM. -The 

bignificance  of  the  pliysical  characters  on  which  the  Natural-History 
system  of  Mineralogy  has  been  based,  and  their  relations  to  the  chemical 
characters  of  the  system  of  Berzelius  and  his  followers,  are  set  forth  in 
the  author's  volume  entitled  A  New  Basis  for  Chemistry,  and  more 
fully  in  his  Mineral  Physiology  and  Physiography,  pages  279-401, 
687, 688,  where  a  tabular  view  of  the  Classes  and  Orders  of  the  Natural 
System  is  given,  on  page  382. 

The  principal  points  in  the  new  treatise  will  be :  (i)  Arrangement  of  all 
native  and  artificial  species  of  the  mineral  kingdom  in  classes  and  orders 
upon  a  chemical  basis;  (2)  Their  complex  chemical  structure  and  high  equiva- 
lent weiglits;  (3)  Application  to  them  of  the  principles  of  polymerism  and  of 
homologous  or  progressive  series;  (4)  Direct  relations  of  the  constitution  of 
solids,  not  only  to  their  specific  gravity,  but  to  their  hardness  and  their 
greater  or  less  chemical  indifference,  which  latter  are  shown  to  be  connected 
with  the  variations  in  condensation  or  so-called  atomic  volume;  (5)  Recogni- 
tion of  the  wide  distinction  between  crystalloid  and  colloid  or  amorphous 
species;  (6)  Sub-division,  on  the  above  grounds,  of  the  orders  and  sub-orders 
into  tribes,  which  generally  correspond  with  the  orders  of  the  Natural-History 
system;  (7)  Arran;j:L'inent  of  tribes  in  genera  and  species,  and  designation  of 
these  by  a  binomial  Latin  nomenclature ;  (8)  Systematic  descriptions  of 
native  and  of  some  related  artificial  species;  (9)  Genetic  history  of  native 
species,  and  their  artificial  production;  (10)  Their  relations  to  the  great 
groups  of  rocks  in  the  earth's  crust 


A  NEW 


BASIS  FOR  CHEMISTRY: 


A  CHEMICAL  PHILOSOPHY. 


BY 


THOMAS  STERRY  HUNT,  M.A.,  LL.D.  (Cantab.), 

AUTHOB    OF    "chemical    AND    OKOLOGICAL    ESSAYS,"    "MINERAL 

PHYSIOLOGY  AND  PHYSIOGRAPHY," 

ETC.,  ETC. 


Omnia  mensura  ot  niimcro  ct  pondnre  disposuistl. 
—  Lib.  Sapientiae,cap.  zX. 


BOSTON: 

SAMUEL    E.   CASSINO. 

1887. 


Copyright,  1886, 
By  Samuel  E.  Cassino. 


\6 


Hq43 


"^VofNewB.?^ 


39009 
2/« 


Elrctrotvpbd 
By  C.  J.  Phters  and  Son,  Boston. 


€a 


J.    B.    STALLO, 

CITIZEN- JURIST-PHILOSOPHER, 

THIS  VOLUME   IS   GRATEFULLY 

DEDICATED   BY  THE 

AUTHOR. 


-r^< 


PREFACE. 


It  is  now  more  than  thirty-eight  years  since 
the  author,  repelled  by  the  contradictions  which 
result  from  the  introduction  into  chemistry  of 
the  atomic   hypothesis,  and    seeking  a   better 
foundation  than  that  on  which  Dalton  endeav- 
ored to  build  a  theory  of  the  science,  began  a 
series  of  publications,  having  for  their  object, 
in  the  words  employed  in   1853,  to  define  the 
"  principles  which  may  serve  as  the  basis  of  a 
sound  theory  of  chemistry,"  and   at  the  same 
time  "to  enlarge  and  simplify  the  plan  of  chem- 
ical science."     In  pursuance  of  this  plan  to  the 
present  time,  he  has  persistently  followed  the 
line  of   argument  foreshadowed   in    1848,   and 
fully  stated  in   1853.     Advances  were  made  in 
the  succeeding  years  ;  but  the  crucial  problem, 
the  solution  of  which  was  required  to  complete 
the  projected  philosophy  of  chemistry,  namely, 
that   of   the   relation   of   equivalent  weight   to 


T  •'  Preface. 

specific  gravity  in  liquids  and  solids,  remained 
unresolved  until  the  summer  of  1886.  With  its 
solution,  the  author  believes  that  the  object  so 
long  ago  proposed  has  been  attained,  and  that 
we  have  the  elements  of  a  new  and  simple 
Chemical  Philosophy,  which  he  ventures  to  des- 
ignate A  New  Basis  for  Chemistry. 

Rejecting  all  hypotheses  regarding  the  con- 
stitution of  matter,  as  irrelevant  to  the  study  of 
chemistry  when  rightly  understood,  and  as  per- 
taining to  the  wholly  distinct  realm  of  dynam- 
ics, the  author  has  attempted  to  define  the 
limit  between  the  two,  and  to  show  that  the 
phenomena  of  solution,  fusion,  volatilization, 
liquefaction,  solidification,  and  crystalHzation, — 
in  a  word,  all  changes  of  state,  — belong  to  the 
domain  of  chemistry,  and  that,  from  a  right 
consideration  of  these,  some  of  the  most  ob- 
scure problems  of  the  science  become  clear. 
He  has  therefore  endeavored,  in  a  series  of 
chapters,  and,  in  large  part,  in  language  quoted 
from  his  earlier  writings,  to  define  the  princi- 
ples upon  which  he  believes  may  one  day  be 
built  a  New  Chemistry. 

The  reader  will  note  that  the  plan  and  the 


Preface. 


vii 


limits  of  this  little  volume  exrUide  the  discus- 
sion  of  many  subjects  which  would  find  a  place 
in  a  systematic  treatise  on  chemical  theory. 
Among  these  are  the  consideration  of  the 
periodic  law  in  relation  to  the  law  of  numbers, 
the  question  of  valency,  and  the  problems  of 
thermo-chemistry,  all  of  which  must  be  reserved 
for  another  time  and  place. 

It  would  be  unjust  on  the  part  of  the  author 
not  to  express  his  many  obligations  to  J.   B. 
Stallo,  now  the  American  Minister  at  the  Court 
of  Italy,  whose  suggestive  volume  on  the  Phi- 
losophy of  Nature,  in  1848,  was,  at  that  early 
date,  a  source  of  inspiration ;  whose  friendship 
during  many  years  has  encouraged  the  writer 
in  his  labors  ;  and  whose  later  volume,  on  The 
Concepts  and  Theories  of  Modern  Physics,  in 
1882,  has  served  to  confirm  him  in  the  position 
which  he  has  long  maintained  with  regard  to 
the   philosophy   of   the    sciences.     To   Stallo, 
therefore,  this  book  is  dedicated. 


Boston,  January  i,  1SS7. 


^  Jfi.)  ipiw 


h 


CONTENTS. 


CHAPTER   I. 

INTRODUCTION. 


A  new  theory  of  chemistry  proposed 

List  of  the  author's  publications  thereon  from  1848  to  1886 

Their  partial  republication  in  1S74  ^nd  18S6 

Their  analysis  and  the  completion  of  the  theory  attempted 


I 
I 

5 
6 


CHAPTER   II. 

NATURE  OF   THE   CHEMICAL   PROCESS. 

Chemistry  as  distinguished  from  physics 

Origin  of  chemical  species  by  metagenesis  and  metamorphosis     .  8 

Metamorphosis  by  expansion  and  by  condensation,  or  polymerism,  8 

Chemical  genealogy ;  double  decomposition 

Polymerism  in  sulphur-vapor  ;  in  carbon  and  phosphorus    ...  10 

Nature  of  double  decomposition  ;  catalysis ,, 

Genealogy  of  species ;  their  homogcneousness j. 

Chemical  identification  and  differentiation jg 

Chemical  integration  and  disintegration j- 

Crystalline  individuality ;  chemism,  dynamics,  biotics    .    .    .    .*  18 

Mineralogy  and  biology ;  physiology  of  matter ,3 

Classification  of  natural  sciences  tabulated jg 

Chemism  often  confounded  with  dynamism 20 

The  activities  of  matter  on  different  planes 21 

Solution  defined  as  chemical  union ^2 

ix 


Contents. 


CHAPTER   III. 

GENESIS   OF   THE  CHEMICAL  ELEMENTS. 

Oken ;  his  Physiophilosophy  and  scheme  of  the  sciences    ...  23 

Genesis  of  elements  from  a  primal  matter 23 

Cosmogony ;  stoichiogeny,  or  the  genesis  of  elements    ....  24 

Studies  of  Dobereiner,  Pettenkofer,  and  Dumas 24 

Prout's  hypothesis  of  equivalent  weights 25 

Brodie's  Calculus  and  his  ideal  elements 26 

Celestial  chemistry  ;  universality  of  dissociation 28 

Brodie's  Ideal  Chemistry  in  relation  to  dissociation 29 

Clarke  on  stellar  chemistry ;  Lockyer's  extension  of  the  view  .    .  31 

Supposed  elemental  matter  in  the  solar  chromosphere     ....  32 

Chemistry  of  nebula; ;  an  interstellar  medium 33 

Genesis  by  condensation  from  primal  matter  restated     ....  35 

The  view  reiterated  by  Mills  and  by  Crookes 36 


CHAPTER   IV. 

GASES,  LIQUIDS,  AND  SOLIDS. 

Relations  between  the  densities  of  gaseous  and  solid  species    .    .  38 

Polymerism  and  high  equivalents  of  solids 39 

The  condensation  in  liouid  species 40 

Liquids  and  solids  as  polymers  of  vapors 41 

Possibility  of  fixing  their  equivalent  weights 42 

CHAPTER  V. 

THE  LAW  OF   NUMBERS. 

Homologous  or  progressive  series  in  chemistry 43 

Organic  chemistry  the  chemistry  of  carbon 44 

Extension  of  the  ■  inception  of  progressive  series 44 

Isomeric  and  anisomeric  homologues 45 

Signilicanc:  of  types  and  structural  formulas 45 

The  bearings  of  the  periodic  law 46 


Coittaits,  jjj 

CHAPTER  VI. 

EQUIVALENT   WEIGHTS. 

The  conception  of  pol3-c.-irbonates  and  polysilicates 
Their  elevated  equivalent  weights 

High  equivalents  in  ammonio-cobalt  salts  and  p'olytungs'tates  ."    '      48 
Complex  inorganic  acids  of  Gibbs 

Summary  of  the  author's  views  in  i8?i  ^^ 

^^ 49 

CHAPTER  VH. 

HARDNESS   AND   CHEMICAL  INDIFFERENCE. 

Density,  hardness,  and  chemical  indiflference  related  ....  r, 

their  connection  with  condensation 

the  doctrine  as  stated  in  1863 

Relations  between  chemical  ai.d  physical  characters  .    .    .'.    \      !! 
Types  of  mineral  silicates ;  porodic  bodies 

Hardness  and  indifference  in  oxyds  and  metallic  species"    .'    .'    ."      !! 

Action  of  fluorhydric  acid  on  silicates \ 

Studies  of  J,  B.  Mackintosh  thereon     ....*.'**''      ^ 


CHAPTER   Vni. 

THE  ATOMIC   HYPOTHESIS. 

Two  hypotheses  as  to  the  constitution  of  matter gg 

The  .-itomic  hypothesis  down  to  Dalton's  time  .......  60 

The  kinetic  theory  of  gases 

Whewell  on  the  difficulties  of  the  atomic  hypothesis  .    .    .    .    .  6,' 

Its  relations  to  chemical  theory 

The  question  of  so-c-illed  molecular  volumes     ......  61 

They  .ire  the  reciprocals  of  the  coefficient  of  condensation   .'    .'    ."  64 

Misconceptions  as  to  the  chemical  jirocess ^. 

Extension  of  the  atomic  hypothesis  from  dynamics'  to  chemistry  .'  66 

Its  mapphcability  to  chemical  phenomena gg 


Xll 


Contents. 


CHAPTER   IX. 

THE   LAW  OF  VOLUMES. 

The  doctrine  of  chemical  equivalents  based  on  volume    ....  68 

The  great  generalization  of  Gay  Lussac 69 

All  things  are  by  measure,  and  number,  and  weight 69 

Universality  of  the  law  of  volumes 70 

Condensation  from  the  gaseous  to  the  solid  state 70 

Supposed  relations  of  volume  to  isomorphism 71 

Conclusions  thereon  of  Dumas  and  others 72 

The  significance  therein  of  crystalline  form  questioned   ....  73 

The  coefficient  of  condensation  determined 75 

Relations  of  density  between  steam  and  water 76 

Relations  between  hydrogen,  steam,  and  water 77 

Equivalent  weights  of  water  and  of  ice 78 

An  expression  sought  for  the  volume 79 

CHAPTER  X. 

METAMORPHOSIS    IN   CHEMISTRY. 

Chemism  defined  ;  metagenesis  and  met.imorphosis 80 

Metamorphosis  as  polymerization  and  depolymerization      ...  81 

Fusion,  vaporization,  and  condensation  are  chemical  changes  ,    .  Si 

Arbitrary  chemical  units  for  non-volatile  species 82 

Metaniorphoses  of  aldehyde 83 

Chloral  and  methylene  oxyd 84 

The  various  turpentine-oils 85 

Pontine  and  its  polymerization 86 

The  lieat  evolved  in  such  changes 87 

Exemplified  by  metallic  oxyds  and  silicates 88 

Metamorphosis  of  sulphur-vapor 89 

Polymerism  of  vapors  under  pressure 90 

Various  liquid  polymers;  forms  of  phosphorus 91 

Metamorphosis  of  tin 92 

Oxygen  and  ozone  ;  iodine  and  chlorine 93 


III 


Contents.  xiii 

Dissociation  a  universal  law     , 

.  94 

Stages  in  chemical  metamorphosis 

Determination  of  the  unit  in  polymerization ^ 

Uhistrations  of  condensation 

Species  soluble  and  insoluble  in  water  '        o 

98 


CHAPTER   XI. 

THE  LAW  OF   DENSITIES. 

The  densities  of  calcium  carbonate  examined ,0 

The  revised  combining  weigiit  of  oxygen  .... 
Variations  in  density  of  related  species 
Breithaupt's  studies  of  the  calcites 
Their  calculated  formulas  and  densities 

The  principle  of  crystalline  admixture "106 

Relations  in  density  of  gases  and  solids '     xoi 

The  reciprocal  of  the  coefficient  of  condensation     ......     ,oS 

Densities  of  water,  steam,  and  hydrogen  compared    .     .'    "    .'     *     ,09 
The  density  of  the  hydrocarbon  butane 

The  formula  p~  d  =  v  considered  . 

no 


CHAPTER   Xn. 

A   HISTORICAL   RETROSPECT. 

The  doctrine  of  high  equivalents  and  complex  formulas      ...     1,2 
Conclusions  of  Favre  and  Silbermann 

Graham  on  polymerism  of  dissolved  salts 

Spencer  Pickering  on  molecular  weights 

Guthrie  on  molecular  equivalents 

Tilden  and  Shenstone  on  sohition  at  high  temperatures'    '.    '.    [     nl 

Louis  Henry  on  the  polymerization  of  oxyds "     ,,s 

Density  as  a  function  of  equivalent  weiglit  ... 

Henry's  inquiry  for  the  coefficient  of  polymerization.'     .    '.    '    '     ]Z 
He  restates  the  author's  argument  of  18;  1 


XIV 


Cojiteiits. 


Oxyds  classified  with  regard  to  polymerization      ......  121 

Henry  Wurtz's  geometrical  chemistry 122 

His  hypothesis  of  varying  molecular  diameters      ......  124 

His  mode  of  calculating  densities  examined 125 

Graham  on  gaseous  and  liquid  diffusion 128 

His  scale  of  solution-densities 130 

His  complex  or  polymeric  molecules 130 

Non-diffusible  bodies,  or  colloids 132 

Favre  and  Silberniann  on  some  chemical  .  iianges 133 

Henri  Sainte-Claire  Deville  on  dissociation 133 

Dissociation  compared  to  evaporation 134 

Diffusion  in  gaseous  dissociation 135 

Combination  compared  to  condensing  of  vapors 136 

Connections  and  consequences  of  the  work  of  Graham  and  Deville,  137 


CHAPTER  XIII. 

CONCLUSIONS. 

The  chemical  process  again  defined 139 

Heterogeneous  and  homogeneous  changes 140 

Metamorphosis  and  polymerization 141 

Varying  stability  of  polymers 142 

Metamorphoses  of  so-called  elements 143 

Genesis  of  elemental  species 143 

Changes  of  state  considered 144 

Condensation  as  related  to  hardness  and  insolubility 145 

The  law  of  volumes  considered 146 

Relations  of  water,  steam,  and  hydrogen  gas 147 

The  proportion  d.pwwv  re-examined 148 

The  coefficient  of  coadcnsation 149 

Density  of  solids  and  liquids  a  function  of  equivalent  weight      .  149 

The  atomic  hypothesis  in  its  relations  to  chemistry 150 

Pressure  as  related  to  chemical  change 151 

Heat  as  the  universal  disintegrator 151 

Relations  of  chemistry  to  dynamics  and  biotics 152 


A  BASIS  FOR  CHEMISTRY. 


CHAPTER   I. 

INTRODUCTION. 

§  I.  At  an  early  period  in  his  chemical  stud- 
ies, the  writer  was  led  to  adopt  certain  principles 
which,  as  said  in  1853,  would,  it  was  thought, 
"be  found  to  enlarge  and  simplify  the  plan  of 
chemical  science,"  and  might  "serve  as  the 
basis  of  a  sound  theory  of  chemistry,"  which  he 
believed  to  be  wanting.  His  principal  publica- 
tions on  this  subject,  from  1848  to  1886,  seven- 
teen in  number,  are  as  follows  :  — 

1.  On  some  Anomalies  in  the  Atomic 
Volumes  of  Sulphur  and  Nitrogen,  with 
Remarks  on  Chemical  Classification  ; 
American  Journal  of  Science  for  September, 
1848  (vi.  170-178). 

2.  On  some  Principles  to  be  Considered 
IN  Chemical  Classification  ;  read  at  the  first . 


i 


m 


2  A  Chemical  Philosophy. 

meeting  of  the  American  Association  for  the 
Advancement  of  Science,  Philadelphia,  Septem- 
ber, 1848,  and  published  in  the  American  Jour- 
nal of  Science  in  1849  (vol-  vii.  399-405  ; 
viii.  89-95). 

3.  A  short  treatise  on  Organic  Chemistry, 
forming  Part  IV,  (pp.  377-538)  of  the  First 
Principles  of  Chemistry  by  B.  Silliman,  Jr., 
third  edition,  1852.  The  novel  points  in 
chemical  theory  in  this  treatise  are  resumed  by 
the  writer  in  the  American  Journal  of  Science 
for  1853  (vol.  XV.  150-152),  and  set  forth  more 
at  length  in  the  next  paper  mentioned. 

4.  On  the  Theory  of  Chemical  Changes 
AND  ON  Equivalent  Volumes  ;  published  in 
March,  1853,  in  the  American  Journal  of 
Science  (xv.  226-234),  reprinted  in  the  same 
year  in  the  London,  Edinburgh,  and  Dublin 
Philosophical  Magazine,  and  in  a  German  trans- 
lation in  the  Chemisches  Centralblatt  (1853, 
page  849). 

5.  On  the  Constitution  and  Equivalent 
Volume  of  some  Mineral  Species  ;  in  the 
American  Journal  of  Science  for  September, 
1853  (xvi.  203-218). 


Introduction. 


n 


6.  Illustrations  of  Chemical  Homol- 
ogy ;  read  before  the  American  Association 
for  the  Advancement  of  Science,  at  Washing- 
ton, May,  1854;  published  in  its  Transactions 
for  that  year  (pages  237-247),  and  in  part  in 
the  last  named  journal  for  September,  1854 
(xviii.  269-271). 

7.  Thoughts  on  Solution  and  the  Chemi- 
cal Process  ;  in  the  American  Journal  of 
Science  for  January,  1855  (xix.  100-103),  and 
in  the  Chemical  Gazette  for  the  same  year, 
page  90. 

8.  The  Theory  of  Types  in  Chemistry; 
in  the  American  Journal  of  Science  for  March, 
1 86 1  (xxxi.  256-264). 

9.  SuR  la  nature  du  Jade  ;  in  the  Compte 
Rendu  of  the  French  Academy  of  Sciences  of 
June  29,  1863,  and  in  an  English  translation  by 
the  author  in  the  American  Journal  of  Science 
for  the  same  year  (xxxvi,  426-428). 

10.  The  Object  and  Method  of  Miner- 
alogy ;  read  before  the  American  Academy  of 
Sciences  in  Boston,  January,  1867,  and  pub- 
lished in  the  American  Journal  of  Science  for 
May  of  that  year  (xliii.  203-206). 


I. 


1!  I 


4  A  CJiemical  PJiilosopliy. 

11.  The  Chemistry  of  the  Primeval 
Earth  ;  a  lecture  before  the  Royal  Institution 
of  Great  Britain,  London,  May  31,  1867,  pub- 
lished in  the  Proceedings  of  the  Institution, 
and  the  Chemical  News  of  June  21,  1867,  sev- 
eral times  reprinted,  and  translated  into  French 
in  Les  Mondes. 

12.  A  Century's  Progress  in  Theoretical 
Chemistry  ;  being  an  address  delivered  at  the 
grave  of  Priestley,  in  Northumberland,  Pennsyl- 
vania, on  the  Centennial  of  Chemistry,  July  3  i, 
1874,  and  published  in  the  American  Chemist 
for  August  and  September  of  that  year. 

13.  The  Chemical  and  Geological  Rela- 
tions OF  the  Atmosphere  ;  published  in  the 
American  Journal  of  Science  for  May,  1880 
(xix.    349-363). 

14.  The  Domain  of  Physiology;  or  Na- 
ture IN  Thought  and  Language  ;  read  be- 
fore the  National  Academy  of  Sciences,  Wash- 
ington, April  18,  1 88 1,  and  published  in  the 
London,  Edinburgh,  and  Dublin  Philosophical 
Magazine  for  October  of  that  year  (V,  xii. 
223-253). 

15.  Celestial  Chemistry  from  the  Time 


Introduction. 


5 


OF  Newton;  read  before  the  Philosophical 
Society  of  Cambridge,  England,  Nov.  28,  1881, 
and  published  in  its  Proceedings  (vol.  IV.  part 
iii)  ;  in  the  Chemical  News,  and  in  the  Ameri- 
can Journal  of  Science  for  February,  1882 
(xxiii.    123-133). 

16.  A  Natural  System  in  Mineralogy, 
WITH  A  Classification  of  Silicates  ;  read 
before  the  National  Academy  of  Sciences,  at 
Washington,  in  April,  1885,  and  before  the 
Royal  Society  of  Canada,  at  Ottawa,  in  May, 

1885,  and  published  in  the  Transactions  of 
the  latter  Society  for  the  same  year  (vol.  III. 
part  iii.  pp.  25-93). 

17.  The  Law  of  Volumes  in  Chemistry; 
published  in  Science  for  September  10,  1886. 

Of  the  above  papers,  4,  7,  8,  10,  and  11,  with 
portions  of  5,  6,  and  9,  were  reprinted  in  the 
author's  Chemical  and  Geological  Essays  (first 
and  second  editions),  in  1874  and  1878;  while 
13,  14,  15,  and  16  appear,  with  some  additions, 
in  his  Mineral  Physiology  and  Physiography,  in 

1886.  A  general  view  of  all  these  was  em- 
bodied in  two  papers,  entitled :  A  Basis  for 
Chemistry;    and    Hardness    and    Chemical 


i 


i  I 


6  A  Chemical  Philosophy. 

Indifference  in  Solids; — read  before  the 
National  Academy  of  Sciences,  in  Boston, 
November  9  and  1 1,  and  noticed  in  Science 
for  November  19,   1886. 

§  2.  The  fundamental  points  in  the  author's 
system  were  already  set  forth  in  the  earlier 
papers,  prior  to  1855  ;  since  which  time  great  ad- 
vances have  been  made  in  dynamical  and  chem- 
ical knowledge.  The  results  of  all  these  lead 
the  writer  to  conclude  that  the  principles  laid 
down  by  him  a  generation  since  should  be  again 
brought  forward,  and  presented  in  a  concise 
form  to  the  attention  of  the  scientific  public, 
with  such  additions  as  are  required  to  complete 
the  philosophy  of  chemistry  then  first  enun- 
ciated. 

The  propositions  which  were  advanced  in  the 
various  publications  named  are  here  set  forth, 
in  large  part  in  language  quoted  from  these, 
in  a  series  of  chapters.  In  making  such  quota- 
tions, reference  is  made  by  appended  numbers 
corresponding  to  those  prefixed  in  the  preced- 
ing list. 


CHAPTER   II. 

NATURE   OF   THE   CHEMICAL    PROCESS. 

§  3-     In    inquiring   into   the   philosophy    of 
chemistry,  it  was  said  in  1853  :  "We  commence 
by   distinguishing   between    those   phenc  .ncna 
which   belong  to   the   domain    of   physics   and 
those  which  belong  to  the  chemical  history  of 
matter.     Under   the   first    head    we    have,   be- 
sides the  gravity  of  matter  in  the  abstract,  its 
various  conditions   of   consistence,   shape,  and 
volume,    with    the    relation   of    the   latter    to 
weight,  constituting   specific   gravity,  and   the 
relations   of   heat,  light,  electricity,    and    mag- 
netism."      These  not  only  "modify  physically 
the  specific  characters  of  matter,  but  they  have 
besides    important    relations   to    those    higher 
processes  which    give   rise   to  new  species"  by 
a  complete  change  in  the  specific  phenomena 
of   bodies.      In   the  capacity  of   such   changes 
consists  the  chemical  activity  of  matter."     Pro- 
ceeding, then,  to  discuss  the  question  of  the 


8 


A  Oiemical  Philosophy. 


origin  of  new  species,  and  the  relations  of  indi- 
viduals, it  was  said  :  "  That  mode  of  generation 
which  produces  individuals  like  the  parent  can 
present  no  analogy  to  the  phenomena  under 
consideration  ;  metagenesis  or  alternate  genera- 
tion, and  metamorphosis,  are,  however,  to  a  cer- 
tain extent,  prefigured  in  the  chemical  changes 
of  bodies."  These  terms  were  then  adopted  in 
chemical  language ;  and  it  was  said  that  meta- 
genesis, or  the  production  of  new  species 
where  two  or  more  are  concerned,  "  is  effected 
in  two  ways :  by  condensation  and  union  on 
the  one  hand,  and  by  expansion  and  division  on 
the  other.  In  the  first  case,  two  or  more  spe- 
cies unite  and  merge  their  specific  character  in 
those  of  a  new  species  ;  in  the  second  case,  the 
process  is  reversed,  and  a  body  breaks  up  into 
two  or  more  new  species."  Of  chemical  meta- 
morphosis, which  embraces  the  phenomena  of 
polymerism,  it  was  said :  "  In  metamorphosis 
by  condensation  only  one  species  is  concerned  ; 
and  in  metamorphosis  by  expansion  the  result 
is  homogeneous  and  without  specific  difference." 
§  4.  "  The  chemical  history  of  bodies  is  a 
record  of  these  changes  ;   it  is,  in  fact,  their 


Nature  of  the  Chemical  Process. 


genealogy.  ...  By  union  we  rise  to  indefi- 
nitely higher  species  ;  but  in  division  a  limit  is 
reached  in  the  production  of  species  which 
seem  incapable  of  farther  division ;  and  these, 
being  regarded  as  primary  or  original  species, 
are  called  chemical  elements."  The  processes 
of  union  and  division  "  continually  alternate 
with  each  other ;  and  a  species  produced  by  the 
first  may  yield  by  division  species  unlike  its 
parents.  From  this  succession  results  double 
decomposition,  or  equivalent  substitution,  which 
always  involves  a  union  followed  by  division; 
although,  under  the  ordinary  conditions,  the 
process  cannot  be  arrested  at  the  intermediate 
stage.  In  the  production  of  hydrochloric  gas 
from  chlorine  and  hydrogen,  union  takes  place, 
followed  by  immediate  expansion  without  spe- 
cific difference  (metamorphosis)  "  ;  while  in  the 
case  of  compounds  of  chlorine  with  hydrocar- 
bons, which,  under  changed  conditions,  break 
up  into  hydrochloric  acid  and  a  chlorinized 
species,  it  was  said,  "  we  observe  the  intermedi- 
ate stage." 

"A  body  may  divide  into  two  or  more  new 
species ;  yet  it  is  evident  that  these  did  not  pre- 


^ 


i  !    S  L 

■*',■:'■ 

■r  \ 


wja 


10 


A  Chemical  Philosophy. 


it! 


ili'l! 


;ii 


exist  in  it,  from  the  fact  that  a  different  divis- 
ion may  yield  other  species  whose  pre-exist- 
ence  is  incompatible  with  the  last ;  nor  can 
the  pre-existence  of  any  species  but  those  which 
we  have  called  primary  be  admitted  as  possible. 
.  .  .  For  these  reasons  it  is  conceived  that  the 
notion  of  pre-existing  elements,  or  groups  of 
elements,  should  find  no  place  in  the  theory 
of  chemistry.  Of  the  relation  which  subsists 
between  the  higher  species  and  those  derived 
from  them,  we  can  only  assert  the  possibility, 
and,  under  proper  conditions,  the  certainty  of 
producing  the  one  from  the  other.  Ultimate 
chemical  analyses  and  the  formulas  deduced 
from  them  serve  to  show  what  changes  are 
possible  in  any  body,  or  to  what  new  species  it 
may  give  rise  by  its  changes."  (4.) 

§  5.  The  question  of  metamorphosis  by  con- 
densation, or  polymerism,  noticed  above,  had 
already  been  discussed  at  some  length  in  1848, 
in  considering  the  vapor-density  of  sulphur, 
when  it  was  shown  that,  if  regarded  as  "  con- 
sisting of  three  equivalents  combined  in  one, 
the  density  of  its  vapor  is  no  longer  an  anom- 
aly, as  the  sulphur-vapor  is  condensed  to  one- 


Nature  of  the  Chemical  Process. 


ir 


third  its  normal  bulk,  and  its  equivalent  num- 
ber  is  i6  X  3  =48"  [32  X  3=  96,  in  the  present 
notation].  It  was  at  the  same  time  proposed 
to  consider  ozone  as  a  similar  triple  group 
(000)  corresponding  to  sulphur-vapor  (SSS) 
and  to  (SOO).  (1.)    Post,  §  56. 

In    the   same   year   these    conclusions   were 
referred  to  in  connection  with  polymerism  in 
hydrocarbonaceous  bodies,  and   allotropism   in 
elements    was    explained   as   polymerism    con- 
nected with   a   change   in   chemical    relations. 
It  was  said  :  "  Those  substances  which  are  con- 
sidered as  elementary  may  change  their  equiva- 
lents, at  the  same  time  undergoing  a  change  in 
their   densities;    and,   as  we  obtain    from    the 
ordinary  equivalent  and  density  an  idea  of  '  the 
volume  of   the  atom,'  we  say  of   those   forms 
having  an  increased  density  and  a  correspond- 
ing increase  of  equivalenL  (so  tliat  the  atomic 
volume  remains  unchanged)  that  two  or  more 
molecules  have   united   in  one.     This   is  illus- 
trated  in   the   case   of   sulphur,"  and,  as   was 
farther  shown,  in  the  compounds  of  mercury, 
copper,  and  iron. 

"The  so-called    elements  may  then   possess 


u 


12 


A  Chemical  Philosophy. 


,11' 


different  atomic  weights,  which  enjoy  a  simple 
relation  to  each  other,  and  in  these  different 
states  exhibit  very  different  characters.  When 
we  speak  of  one  of  these  as  containing  two  or 
three  atoms  of  another  form  condensed  into 
one,  it  is  only  an  expression  in  accordance  with 
previously  existing  ideas.  We  can  no  longer 
attach  to  the  atomic  weights  of  the  supposed 
elements  an  absolute  value  [that  is,  as  being 
the  weight  of  an  absolutely  elemental  species] ; 
and  thus  one  of  the  characteristics  which  serve 
to  distinguish  them  from  known  compounds  is 
rendered  of  no  importance."  In  farther  illus- 
tration of  this  conception,  it  was  then  and 
there  suggested  that  charcoal,  graphite,  and 
diamond  being  "  polymeric  modifications  of 
elemental  carbon,"  the  first  of  these  "  is  a  spe- 
cies of  anhydrid  derived  from  cellulose  "  ;  and, 
moreover,  that  the  allotropic  red  phosphorus 
might  be  a  similar  polymer; — a  question  which, 
it  was  said,  "would  be  solved  by  a  determina- 
tion of  its  density  in  that  state."  (2.) 

§  6.  In  1854,  returning  to  the  subject  of 
chemical  change,  and  discussing  the  question 
of  double  decomposition,  it  was  illustrated  by 


Nature  of  the  CJicmical  Process. 


13 


the  production  of  arsenious  oxycl  and  chlorhydric 
acid  by  the  action  of  water  on  terchlorid  of 
arsenic,  when  it  was  said  :  "  This  decomposi- 
tion of  the  sokition  of  chlorid  of  arsenic  is  an 
example  of  Avhat  is  generally  called  double  elec- 
tive affinity  {attractio  electiva  duplex),  and  is 
generally  explained  by  saying  that  the  attrac- 
tion of  arsenic  for  oxygen,  and  that  of  chlorine 
for  hydrogen,  enable  the  chlorid  and  the  water 
to  decompose  each  other.  But  these  elemental 
species  tlo  not  exist  in  the  solution,  although 
they  are  possible  results  of  its  decomposition ; 
and  to  explain  the  process  in  this  manner  is 
to  ascribe  it  to  the  affinities  of  yet  unformed 
species." 

It  was  farther  said  that  "  double  decomposi- 
tion always  involves  union  followed  by  division  ; 
although  we  cannot  in  every  case  arrest  the 
process  at  its  first  stage.  Under  some  changed 
conditions  of  temperature  and  pressure  the  de- 
composition may  be  counterpart  of  the  previous 
union  "  ;  as  in  the  example  then  given  of  mer- 
cury and  o.xygen.  "  When  the  division  takes 
place  in  a  sense  different  from  the  union,  giving 
rise  to  new  species,  we  have  double  decomposi- 


^m 


14 


A  Chemical  Philosophy. 


m\\\ 


iii; 


tion,  ...  It  is  only  when  looked  upon  as  a 
momentary  combination,  followed  by  a  decom- 
position, that  the  theory  of  double  decomposi- 
tion becomes  intelligible  and  is  in  accordance 
with  known  facts.  From  the  narrow  limits  of 
temperature  which  often  include  the  processes, 
and  from  the  ease  with  which  light,  warmth, 
friction,  and  pressure  excite  the  decomposition 
of  such  bodies  as  the  chlorid  of  nitrogen,  the 
nitrite  of  ammonia,  the  oxyds  of  chlorine,  and 
the  metallic  fulminates,  we  may  conclude  that 
within  still  narrower  limits,  and  under  condi- 
tions as  yet  undefined,  many  bodies  may  exhibit 
affinities  for  each  other  which  are  reversed  by 
a  very  slight  change  of  condition.  In  this  way 
we  may  explain  many  of  those  obscure  phenom- 
ena hitherto  ascribed  to  action  by  presence  or 
catalysis."  {7.) 

§  7.  The  above  doctrines  were  restated  in 
1861,  as  follows:  "All  chemical  changes  are 
reducible  to  union  (identification)  and  division 
(differentiation).  When  in  these  changes  only 
one  species  is  concerned,  we  designate  the 
process  as  metamorphosis,  which  is  either  by 
condensation  or  by  expansion  (homogeneous  dif- 


Nature  of  the  Chemical  Process. 


IS 


ferentiation).  In  metagenesis,  on  the  contrary, 
unlike  species  may  unite  and,  by  a  subsequent 
heterogeneous  differentiation,  give  rise  to  new 
species,  constituting  what  is  called  double  de- 
composition ;  the  results  of  which,  differently 
interpreted,  have  given  rise  to  the  hypothesis 
of  radicles,  and  the  notion  of  substitution  by 
residues,  to  express  the  relations  between  the 
parent  bodies  and  their  progeny.  The  chemi- 
cal history  of  bodies  is  a  record  of  these 
changes ;  it  is,  in  fact,  their  genealogy,  and 
in  making  use  of  typical  formulas  to  indicate 
the  derivation  of  chemical  species,  we  should 
endeavor  to  show  the  ordinary  modes  of  gen- 
eration." (8.) 

§  8.  In  farther  exposition  of  the  nature  of 
the  chemical  process,  it  was  said  in  1853 : 
"  Chemical  species  are  homogeneous  ;  tota  in 
minimis  cxistit  naturay  "  Chemical  combina- 
tion is  not  a  putting  together  of  molecules,  but 
an  interpenetration  of  masses."  "  Chemical 
union  is  interpenetration,  as  taught  by  Kant,  and 
not  juxtaposition,  as  conceived  by  the  atomistic 
chemists.  When  bodies  unite,  their  bulks,  like 
their  specific  characters,  are  lost   in  those  of 


«S{ 


-^\\ 


'  ( 


.  i 


M 


i6 


A  Clicviical  Philosophy, 


the  new  species."  (4.)  In  the  year  1855  it 
was  farther  said  of  Kant's  definition,  that  "the 
conception  is  mechanical,  and  therefore  fails 
to  give  an  adequate  idea.  The  definition  of 
Hegel,  that  the  chemical  process  is  an  identifica- 
tion of  the  different  and  a  differentiation  of 
the  identical,  is,  however,  completely  adequate. 
Chemical  union  involves  an  identification  not 
only  of  the  volumes  (interpenetration  mechani- 
cally considered),  but  of  the  specific  character 
of  the  combining  bodies,  which  are  lost  in 
those  of  the  new  species,"  (7.)  In  farther 
illustration  of  the  above  conception,  in  1867, 
in  referring  to  the  speculations  of  Macvicar  and 
Gaudin,  as  to  "  the  arcj;iitecture  of  crystalline 
molecules,"  it  was  written  :  "  Nature  builds  up 
her  units  by  interpenetration  and  identification, 
and  not  by  juxtaposition  of  the  chemical  ele- 
ments." (10.) 

§9,  In  1874,  in  again  discussing  this  ques- 
tion, it  was  said  :  *'  In  chemical  change  the 
uniting  bodies  come  to  occupy  the  same  space 
at  the  same  time,  and  the  impenetrability  of 
matter  is  seen  to  be  no  longer  a  fact.  The 
volume  of   the   combining  substances   is  con- 


Nature  of  the  Chemical  Process. 


17 


founded,  and  all  the  physical  and  physiological 
characters  which  are  our  guides  in  the  region 
of    physics    fail    us,    gravity    alone    excepted. 
The   diamond   dissolves    in    oxygen,    and    the 
identities    of    chlorine    and    sodium    are    lost 
i^    that    of    sea-salt.      To    say   that   chemical 
union    is,    in    its     essence,    identification,    as 
Hegel   has   defined   it,   seems  to  me  the  sim- 
plest   statement     conceivable.      The    type    of 
the    chemical    process    is    found    in    solution, 
from  which  it  is  possible,  under  changed  physi- 
cal    conditions,    to     regenerate     the     original 
species."    (12.) 

§  10.   Chemical  change,  then,  may  be  defined 
as  an  integration  or  a  disintegration  of  chemi- 
cal   species,   resulting   in   the  genesis   of   new 
species,  which  are  themselves  chemical ;   that 
is   to  say,   mineral,   and    not    organic.     All   of 
these  "  may  be  supposed  to  be  formed  from  a 
single  element,  or  materia  prima,  by  the  chemi- 
cal  process."     "The  chemical  species,  until  it 
attains  to  individuality  in  the  crystal,  is  essen- 
tially quantitative."  (10.)      Gases,  liquids,  and 
colloids  have  a  specific  existence,  but  no  indi- 
viduality;     mechanical    subdivision    does    not 


i**! 


\   i 


i*J 


i8 


A  CJiemical  Philosophy. 


destroy  them.  "  The  activities  of  the  crystal 
are  purely  dynamic,  and  its  crystalline  individ- 
uality must  be  destroyed  before  it  can  be  the 
subject  of  chemism,  while  the  plant  and  the 
animal  exhibit  not  only  dynamical  and  chemical, 
but  organogenic  activities,  which  last  are  desig- 
nated as  vital  phenomena."  All  of  these  are 
necessary  for  the  preservation  of  the  organism. 
The  study  of  these  vital  activities  constitutes  a 
third  division  of  physics,  which  we  have  else- 
where called  biotics. 

**  Mineralogy  is  the  science  of  inorganic  mat- 
ter, and  studies  its  dynamical  and  chemical 
relations  ;  while  biology,  which  is  the  science 
of  organic  matter,  adds  to  these  the  study  of 
biotical  relations.  The  dynamical  and  chemi- 
cal activities  which,  in  the  mineral  kingdom, 
give  rise  to  the  crystalline  individual,  are 
therein  in  static  equilibrium.  The  organic 
individual,  on  the  contrary,  is  kinetic,  and 
maintains  its  equilibrium  by  perpetual  ad- 
justment with  the  outer  world,"  **  The 
physiology  of  matter  in  the  abstract  is 
dynamical ;  that  of  mineral  forms  is  both 
dynamical  and  chemical ;  while  that  of  organic 


Nature  of  the  Chemical  Process. 


19 


forms    is    at   once   dynamical,    chemical,    and 
biotical."  (14.)^ 

§  II.  By  keeping  in  mind  the  above  defini- 
tions, we  shall  avoid  the  error  of  modern 
students,  who  are  disposed  to  confound  dyn- 
amic activities  with  chemism  itself,  and  thus 
to  lose  sight  of  the  essential  nature  of  the 
chemical  process,  which,  as  was  pointed  out  in 
1853  (§  3),  is  to  be  clearly  distinguished  from 

'  These  relations  will  be  made  more  apparent  by  the  help  of 
a  tabular  view  of  the  classification  of  the  natural  sciences  from 
the  writer's  Mineral  Physiology  and  Physiography,  page  29. 


Natural  Sciences. 

Inorganic  Nature. 

Organic  Nature. 

Descriptive, 

Mineral  Physiography. 

Biophysiography. 

General  Physiography 

Descriptive  and  Systematic 

Organography  ; 

or 

Mineralogy ; 

Descriptive  and  Syste- 

Natural History. 

Geognosy ;    Geography ; 

matic  Botany  and 

Descriptive  Astronomy. 

Zoology. 

Philosophical. 

Mineral  Physiology. 

Biophysiologv. 

General  Physiology 

Dynamics  or  Physics ; 

Biotics. 

or 

Chemistry. 

Organogeny;  Morpho- 

Natural Philosophy. 

Geogeny ;   Theoretical 

logy;  Physiological 

Astronomy. 

Botany  and  Zoology. 

■■■%• 

Ij 

\\ 

In  I 

iii 


.1  \ 


ii 


20 


A  Chemical  Pliilosophy. 


the  phenomena  belonging  to  what  we  may  call 
dynamism.  As  examples  of  this  prevailing 
confusion,  it  was  said,  in  1881  :  "  Clifford  wrote 
of  molecular  motion,  '  which  makes  itself  known 
as  light,  or  radiant  energy,  or  chemical  action ' ; 
while  Faraday  was  wont  '  to  express  his  convic- 
tion that  the  forces  termed  chemical  affinity 
and  electricity  are  one  and  the  same.'  Helm- 
holtz,  from  whom  I  here  quote,  adds  :  '  I  think 
the  facts  leave  no  doubt  that  the  very  mightiest 
among  the  chemical  forces  are  of  electrical 
origin  .  .  .  but  I  do  not  suppose  that  other 
molecular  forces  are  excluded,  working  directly 
from  atom  to  atom.'  "  Similar  language  might 
be  quoted  from  other  not  less  eminent  authori- 
ties, to  show  the  vague  notions  still  reigning  in 
the  minds  of  modern  students  as  to  the  scope 
of  chemistry,  and  its  relation  to  dynamics. 

"The  activities  which  appear  in  dynamical 
and  in  chemical  phenomena  are  one  in  essence, 
for  force  is  one.  The  same  is  true  of  the  activ- 
ities manifested  in  organic  growth,  and  even  in 
thought ;  but  the  unity  and  mutual  convertibil- 
ity of  different  manifestations  of  force  afford  no 
ground   for   confounding,   as   some   would   do, 


Nature  of  the  Chemical  Process. 


21 


dynamics  with  chemism,  or  with  vital  or  mental 
processes.  All  these  phenomena  arc  but  evi- 
dences of  universal  animation ;  or,  in  other 
words,  of  an  energy  which  is  inherent  in 
matter,  the  manifestations  of  which,  as  matter 
rises  to  higher  stages  of  development,  become 
more  complex,  as  organic  individuals  are  them- 
selves more  complex  than  mineral  forms." 

"  When  the  energy  which  is  in  matter  is 
manifested  without  reference  to  species,  we 
call  it  simply  dynamics ;  when  it  results  in  the 
production  of  mineral  species,  we  call  it  chem- 
ics,  or  chemism ;  and  when  it  gives  rise  to 
organisms,  which  may  be  defined  as  kinetic 
individuals,  we  distinguish  it  as  vital,  or  biotic. 
In  matter  we  must  recognize,  with  Tyndall, 
*  the  promise  and  the  potency  of  all  terrestrial 
life.'"  (14.)  Those  dynamic  activities  which 
manifest  themselves  as  electricity,  temperature, 
and  radiant  energy,  while  attendant  upon  chem- 
ical processes,  are  yet  to  be  as  carefully  dis- 
tinguished from  the  essential  phenomena  of 
chemism  as  the  latter  are  from  those  of  biotics. 

§  12.  In  farther  illustration  of  the  nature  of 
chemical   combination,    it   was   said,    in    1853  : 


1: 

I' 


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'11 


!il 


22 


A  Chemical  Philosophy. 


"  Solution  is  a  result  of  that  tendency  in  nature 
which  constantly  leads  to  unity,  condensation, 
identification."  "  Solution  is  chemical  union, 
as  is  indicated  by  the  attendant  condensation." 
(4.)  Again,  in  1855,  it  was  written:  "All 
chemical  union  is  nothing  else  than  solution  ; 
the  uniting  species  are,  as  it  were,  dissolved  in 
each  other;  for  solution  is  mutual."  "  Solution, 
then,  being  identification,  the  discussion  as  to 
whether  metallic  chlorids  are  changed  into 
hydrochlorates  when  dissolved  in  water  is 
meaningless.  Such  a  solution  is  a  unity,  in 
which  we  can  no  more  assert  the  existence  of 
the  chlorid,  or  of  water,  than  of  chlorine,  hydro- 
chloric acid,  or  a  metallic  oxyd  ;  although  these, 
and  many  others,  are  conceivable  results  of  its 
differentiation."  (7.)  In  the  words  already  cited, 
—  "The  type  of  the  chemical  process  is  found 
in  solution,  from  which  it  is  possible,  under 
changed  physical  conditions,  to  regenerate  the 
original  species."  (12.) 


CHAPTER   III. 

GENESIS    OF    THE   CHEMICAL    ELEMENTS. 

§  13.  There  remains  to  be  considered  an- 
other aspect  of  the  chemical  process  —  namely, 
the  production,  from  a  primal  undifferentiated 
matter,  of  the  chemical  elements,  as  suggested 
by  Lorenz  Oken.'     "  The  successive   steps  in 

^  In  this  connection  we  quote  from  page  3  of  Tulk's  Trans- 
lation of  Oken's  Physiophiiosophy,  pul)lished  by  the  Ray 
Society  in  1847,  with  a  preface  by  Oken  himself,  the  following 
passage :  "  Physiophiiosophy  is  divisible,  therefore,  into  three 
parts.  .  .  .  The  first  division  is  the  doctrine  of  the  Whole 
{i/e  Toto)  —  Mathesis.  The  second  that  of  Singulars  {de  Eiiti- 
liiis)  —  Ontology.  The  third  that  of  the  Whole  in  Singulars 
(de  Toto  in  Entibiis)  —  Biology.  The  science  of  the  Whole 
must  divide  itself  into  two  doctrines ;  into  that  of  immaterial 
totalities — Pneumatogeny;  and  that  of  material  totalities  — 
Hylogeny.  Ontology  teaches  us  the  phenomena  of  matter. 
The  first  phenomena  of  this  are  the  heavenly  bodies,  compre- 
hended by  Cosmogony.  These  develop  themselves  further, 
and  divide  [differentiate]  into  the  elements  —  Stoichiogeny. 
From  these  the  earth-element  develops  itself  still  further,  and 
divides  into  minerals  —  Mineralogy.  These  minerals  unite  in 
one  collective  body,  and  this  is  Geogcny.  The  Whole  in 
Singulars  is  the  living  or  Organic,  which  again  divides  into 
plants  and  animals."  The  study  of  these  includes  Biology, 
with  its  subdivisions. 

23 


ti 


-J-T-  , 


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■Ul  \ 


1 

1 

1' 

H 


A  Chemical  Philosophy. 


m 


the  ontological  process  are,  first,  Cosmogony,  or 
the  fashioning  of  the  heavenly  bodies  from  the 
previously  formed  matter  ;  followed  by  the  gen- 
esis therefrom  of  the  chemical  elements,  Stoi- 
chiogeny."  (14.) 

§  14.  The  conception  of  the  genesis  of  the 
so-called  chemical  elements  first  took  a  definite 
form  from  the  study  of  the  equivalent  weights 
of  related  elements,  and  from  the  law  of  num- 
bers made  apparent  in  hydrocarbonaccous  bod- 
ies. Of  this  we  wrote  as  follows,  in  1874,  in 
the  essay  on  A  Century's  Progress  in  Theoreti- 
cal Chemistry  (12)  :  — 

"As  early  as  1829,  Dobereiner  called  atten- 
tion to  the  triads  of  related  bodies,  such  as  the 
groups  of  lithium,  sodium,  and  potassium,  and 
of  calcium,  strontium,  and  barium,  in  which 
the  equivalent  weight  of  the  middle  term  is 
the  mean  of  that  of  the  extremes.  Almost 
simultaneously,  and  apparently  independently, 
Pettenkofer  and  Dumas  took  up  again  the 
question,  in  185 1,  and  noticed  the  fact  that 
the  numerical  relations  between  these  and 
many  other  mineral  radicles  are  similar  to 
those  between  the  organic  radicles  known  to 


Genesis  of  the  Chemical  Elements.         25 

result  from  the  condensation  of  successive 
equivalents  of  carbon  and  hydrogen,  such  as 
the  olefines,  the  paraffines,  and  the  alcohol 
radicles.  The  possibility  that  the  mineral 
radicles,  related  alike  in  chemical  characters 
and  in  equivalent  weights,  might,  also,  be  com- 
posite bodies,  was  suggested  by  Dumas  in 
1857;  and  with  this  in  view  he  undertook  a 
re-examination  of  the  equivalent  weights  of 
the  elements.  If,  as  the  numbers  adopted  by 
Berzelius  seemed  to  show,  no  simple  ratios 
existed  between  those  of  related  elements,  the 
suggestion  of  Dumas  was  inadmissible  ;  but  if, 
on  the  contrary,  as  supposed  by  Prout,  a  simple 
and  exact  relation  of  this  kind  was  established, 
it  was  not  impossible  that  the  view  of  their 
compound  nature  might  be  true." 

'*  The  results  of  many  years  of  patient  labor 
devoted  to  a  re-examination  of  the  equivalent 
weights  of  a  great  number  of  bodies,  were 
given  to  the  world  by  Dumas,  in  1859;  and 
from  these  he  concluded  that  the  law  of  Prout 
is  so  far  true  that  the  equivalent  weights  of 
the  elements  are  multiples  of  a  unity  which  is 
one-fourth   that   of    hydrogen.  .  .  .  These    re- 


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26 


A  Chemical  Philosophy. 


Ml 


suits,  and  the  analogies  between  the  elements 
of  mineral  and  of  organic  chemistry,  both  in 
chemical  relations  and  in  equivalent  weights 
(which  in  the  mean  time  had  been  carefully 
investigated  and  developed  by  J.  P.  Cooke),  now 
led  Dumas  to  reafHrm  his  conjecture  that  the 
mineral  radicles  may  really  be  compounds, 
though  their  decomposition  is  perhaps  beyond 
the  possibilities  of  our  chemical  analysis."  (12.) 

§  15.  The  next  step  in  the  development  of 
the  doctrine  of  Stoichiogeny,  so  far  as  known 
to  the  writer,  is  to  be  found  in  his  lecture  of 
1867  (11),  quoted  below.  The  history  thereof, 
and  of  certain  views  enunciated  almost  simul- 
taneously by  Brodie  of  Oxford  and  the  present 
writer,  and  subsequently  developed  and  ex- 
tended by  the  latter,  is  given  at  length  in  his 
essay  on  Celestial  Chemistry  from  the  Time  of 
Newton  (15),  as  follows  :  — 

"  In  Part  I.  of  his  Calculus  of  Chemical 
Operations,  read  before  the  Royal  Society, 
May  3,  1866,  and  published  in  the  Philosophi- 
cal Transactions  for  that  year,  Brodie  was  led 
to  assume  the  existence  of  certain  ideal  ele- 
ments.    These,  he  said,  '  though  now  revealed 


Gcfiesis  of  the  Chemical  Elements.         27 

to  us  through  the  numerical  properties  of  chem- 
ical equations  only  as  implicit  and  dependent 
existences,  we  cannot  but  surmise  may  some- 
times become,  or  may  in  the  past  have  been, 
isolated  and  independent  existences*  Shortly 
after  this  publication,  in  the  spring  of  1867,  I 
spent  several  days  in  Paris  with  the  late  Henri 
Sainte-Claire  Devillc,  repeating  with  him  some 
of  his  remarkable  experiments  in  chemical  dis- 
sociation, the  theory  of  which  we  then  discussed 
in  its  relations  to  Faye's  solar  hypothesis. 
From  Paris,  in  the  month  of  May,  I  went,  as 
the  guest  of  Brodie,  for  a  few  days  to  Oxford, 
where  I  read  for  the  first  time,  and  discussed 
with  him,  his  essay  on  the  Calculus  of  Chemi- 
cal Operations,  in  which  connection  occurred 
the  very  natural  suggestion  that  his  ideal  ele- 
ments might,  perhaps,  be  liberated  in  solar  fires, 
and  thus  be  made  evident  to  the  spectroscope." 
§  15  A.  "I  was  then  about  to  give,  by  invita- 
tion, a  lecture  before  the  Royal  Institution,  on 
The  Chemistry  of  the  Primeval  Earth,  which 
was  delivered  May  31,  1867.  A  stenographic 
report  of  the  lecture,  revised  by  the  author, 
was  published  in  the  Chemical  News  of  June 


■' ) 


1 1' 

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1 

^IF 


28 


A  Chemical  Philosophy. 


21,  1867,  and  in  the  Proceedings  of  the  Royal 
Institution.  Therein,  I  considered  the  chem- 
istry of  nebulas,  sun,  and  stars  in  the  combined 
light  of  spectroscopic  analysis  and  Deville's 
researches  on  dissociation,  and  concluded  with 
the  generalization  that  the  *breaking-up  of 
compounds,  or  dissociation  of  elements,  by 
intense  heat  is  a  principle  of  universal  applica- 
tion, so  that  we  may  suppose  that  all  the  ele- 
ments which  make  up  the  sun,  or  our  planet, 
would,  when  so  intensely  heated  as  to  be  in 
the  gaseous  condition  which  all  matter  is  capa- 
ble of  assuming,  remain  uncombined  ;  that  is  to 
say,  would  exist  together  in  the  state  of  chem- 
ical elements  ;  whose  further  dissociation  in 
stellar  or  nebulous  masses  may  even  give  us 
evidence  of  matter  still  more  elemental  than 
that  revealed  in  the  experiments  of  the  labora- 
tory, where  we  can  only  conjecture  the  com- 
pound nature  of  many  of  the  so-called  ele- 
mentary substances '  (11)." 

§  16.  "The  importance  of  this  conception,  in 
view  of  subsequent  discoveries  in  spectroscopy 
and  in  stellar  chemistry,  has  been  well  set  forth 
by  Lockyer,  in  his  late  lectures  on  Solar  Phys- 


Genesis  of  the  Chemical  Elements.         29 

ics,^  where,  however,  the  generalization  is  de- 
scribed as  having  been  first  made  by  Brodie, 
in  1867.  A  similar  but  later  enunciation  of 
the  same  idea  by  Clerk-Maxwell  is  also  cited 
by  Lockyer.  Brodie,  in  fact,  on  the  6th  of 
June,  one  week  after  my  own  lecture,  gave  a 
lecture  on  Ideal  Chemistry  before  the  Chemi- 
cal Society  of  London,  published  in  the  Chemi- 
cal News  of  June  14,  in  which,  with  regard 
to  his  ideal  elements  (in  further  extension  of 
the  suggestion  already  put  forth  by  him  in  the 
extract  above  given  from  his  paper  of  May  6, 
1866),  he  says:  *  We  may  conceive  that  in 
remote  ages  the  temperature  of  matter  was 
much  higher  than  it  is  now,  and  that  these 
other  things  [the  ideal  elements]  existed  in  the 
state  of  perfect  gases  —  separate  existences  — 
uncombined.'  He  further  suggested,  from 
spectroscopic  evidence,  that  it  is  probable  that 
'  we  may  one  day,  from  this  source,  have  re- 
vealed to  us  independent  evidence  of  the 
existence  of  these  ideal  elements  in  the  sun 
and  stars.'  During  the  months  of  June  and 
July,  1867,  I  was  absent  on  the  Continent; 
1  Nature,  Aug.  25,  188 1,  vol.  xxiv.  p.  396. 


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30 


A  Chemical  Philosophy. 


and  this  lecture  of  Brodie's  remained  wholly 
unknown  to  me  until  its  republication  in  1880, 
in  a  separate  form,  by  its  author/  with  a 
preface,  in  which  he  pointed  out  that  he  had 
therein  suggested  the  probable  liberation  of 
his  ideal  elements  in  the  sun,  referring  at  the 
same  time  to  his  paper  of  1866,  from  which 
we  have  already  quoted  the  only  expression 
bearing  on  the  possible  independence  of  these 
ideal  elements  somewhere  in  time  or  in  space." 
"  The  above  statements  are  necessary  in  order 
to  explain  why  it  is  that  I  have  made  no  refer- 
ence to  Sir  Benjamin  Brodie  on  the  several 
occasions  on  which,  in  the  interval  between 
1867  and  the  present  time  [1881],  I  have  re- 
iterated and  enforced  my  views  on  the  great 
significance  of  the  hypothesis  of  celestial  disso- 
ciation as  giving  rise  to  forms  of  matter  more 
elemental  than  any  known  to  us  in  terrestrial 
chemistry.  The  conception,  as  at  first  enunci- 
ated, in  somewhat  different  forms,  alike  by 
Brodie  and  myself,  was  one  to  which  we  were 
both  naturally,  one  might  say  inevitably,  led,  by 
different  paths,  from  our  respective   fields  of 

1  Ideal  Chemistry,  a  Lecture.    Macmillan,  1S80. 


Genesis  of  the  Chemical  Elements.         31 

speculation,  and  which  each  might  accept  as  in 
the  highest  degree  probable,  and  make,  as  it 
were,  his  own.  I  write,  therefore,  in  no  spirit  of 
invidious  rivalry  with  my  honored  and  lamented 
friend,  but  simply  to  clear  myself  from  the 
charge,  which  might  otherwise  be  brought 
against  me,  of  having,  on  various  occasions 
within  the  past  fourteen  years,  put  forth  and 
enlarged  upon  this  conception  without  mention- 
ing Sir  Benjamin  Brodic,  whose  only  publica- 
tion on  the  subject,  so  far  as  I  am  aware,  was 
his  lecture  of  1867,  unknown  to  me  until  its 
reprint  in   1880." 

§  17.  "It  was  at  the  grave  of  Priestley,  in 
1874,  that  I  for  the  second  time  considered  the 
doctrine  of  celestial  dissociation,  commencing 
with  an  account  of  the  hypothesis  put  forward  by 
F.  W.  Clarke,  of  Cincinnati,  in  January,  1873,^ 
to  explain  the  growing  complexity  which  is 
observed  when  we  compare  the  spectra  of  the 
white,  yellow,  and  red  stars  ;  in  which  he  saw 
evidence  of  a  progressive  evolution  of  chemical 
species,  by  a  stoichiogenic  process,  from  more 


11 


If' 


n 


1  Clarke,   "Evolution    and    the    Spectroscope,"    Topular 
Science  Monthly,  New  York,  vol.  ii.  p.  32. 


■11 


32 


A  Chemical  Philosophy. 


I  1 


! 


elemental  forms  of  matter.  I  then  referred  to 
the  further  development  of  this  view  by  Lock- 
yer,  in  his  communication  to  the  French  Acad- 
emy of  Sciences  in  November  of  the  same  year, 
wherein  he  connected  the  successive  appear- 
ance in  celestial  bodies  of  chemical  species  of 
higher  and  higher  vapor-densities  with  the 
speculations  of  Dumas  and  Pettenkofer  as  to 
the  composite  nature  of  the  chemical  elements.  ^ 
I  next  quoted  from  my  lecture  of  1S67  the 
language  already  cited  (on  page  28),  to  the 
effect  that  dissociation  by  intense  heat  in  stel- 
lar worlds  might  give  us  more  elemental  forms 
of  matter  than  any  known  on  earth.  It  was 
further  suggested  that  the  green  line  in  the 
spectrum  of  the  solar  corona  (which  had  been 
supposed  to  indicate  a  hitherto  unknown  sub- 
stance, that,  *  from  its  extension  beyond  even 
the  layer  of  partially  cooled  hydrogen,  must, 
according  to  the  deductions  of  Mr.  George  J. 
Stoney,  be  still  lighter  than  this  gas')  may 
be  due  to  a  'more  elemental  form  cf  matter, 
which,  though  not  seen  in  the  nebulai,  is  libera- 
ted by  the  intense  heat  of  the  solar  sphere,  and 

1  Lockyer,  Comptes  Rendus,  Nov.  3,  1873. 


Genesis  of  the  Chemical  Elements.         33 


m 


^,i:r  \ 


may  possibly  correspond  to  the  primary  matter 
conjectured  by  Dumas,^  having  an  equivalent 
weight  one-fourth  that  of  hydrogen.'  (12.)  The 
suggestion  of  Lavoisier,  that  *  hydrogen,  nitro- 
gen, and  oxygen,  with  heat  and  light,  might  be 
regarded  as  simpler  forms  of  matter  from  which 
all  others  are  derived,'  was  also  noticed  in  con- 
nection with  the  fact  that  the  nebulae,  which  we 
conceive  to  be  condensing  into  suns  and  planets, 
have  hitherto  shown  evidences  only  of  the  pres- 
ence of  the  first  two  of  these  elements  ;  which,  as 
is  well  known,  make  up  a  large  part  of  the  gas- 
eous envelope  of  our  planet,  in  the  forms  of 
air  and  aqueous  vapor.  With  this  I  connected 
the  hypothesis  that  our  atmosphere  and  ocean 
are  but  portions  of  the  universal  medium  which, 
in  an  attenuated  form,  fills  the  interstcllary 
spaces ;  and  further  suggested  as  '  a  legitimate 
and  plausible  speculation,'  that  '  these  same 
nebulae    and    their    resulting   worlds    may   be 

1  In  the  paper  of  1874,  it  was  farther  said  in  this  con- 
nection :  "  Mention  should  also  be  made  of  the  unknown  ele- 
ment conjectured  by  Huggins  to  exist  in  some  nebulae.  This 
conception  of  a  first  matter,  or  Urstoff,  has  also  been  main- 
tained by  Ilinrichs,  who  has  put  forward  an  argument  in  its 
favor  from  a  consideration  of  the  wave-lengths  in  the  lines  of 
the  spectra  of  various  elements." 


m 


1 

w 


1  \ 


i 


34 


A  Chemical  Philosophy. 


evolved  by  a  process  of  chemical  condensation 
from  this  universal  atmosphere,  to  which  they 
would  sustain  a  relation  somewhat  analogous  to 
that  of  clouds  and  rain  to  the  aqueous  vapor 
around  us.'" 

§  1 8.  "These  views  were  reiterated  in  the 
preface  to  a  second  edition  of  my  Chemical 
and  Geological  Essays,  in  1878,  and  again 
before  the  British  Association  for  the  Advance- 
ment of  Science,  at  Dublin,^  and  before  the 
French  Academy  of  Sciences  in  the  same 
year.2  They  were  still  further  developed  in 
the  essay  on  The  Chemical  and  Geological 
Relations  of  the  Atmosphere,  published  in 
1880  (13),  in  which  attention  was  called  to 
the  important  contribution  to  the  subject 
by  Mr.  Lockyer,  in  his  ingenious  and  beauti- 
ful spectroscopic  studies,  the  results  of  which 
are  embodied  in  his  *  Discussion  of  the  Work- 
ing Hypothesis  that  the  so-called  Elements 
are  Compound  Bodies,'  communicated  to  the 
Royal  Society,  Dec.  12,  1878.  It  was  then 
remarked  that  the  already  noticed  *  speculation 


1  Nature,  Aug.  29,  1878,  vol.  xviii.  p.  475. 

2  Comptes  Rendus,  Sept.  23,  1878,  vol.  xxxviii.  p.  452. 


Genesis  of  the  Chemical  Elements,         35 

of  Lavoisier  is  really  an  anticipation  of  that 
view  to  which  spectroscopic  study  has  led 
the  chemists  of  to-day  ' ;  while  it  was  said  that 
the  hypothesis  put  forth  by  the  writer  in  1874, 
'  which  seeks  for  a  source  of  the  nebulous  mat- 
ter itself,  is,  perhaps,  a  legitimate  extension  of 
the  nebular  hypothesis.*"  (15.) 

§  19.  That  the  law  of  chemical  dissociation 
by  heat  is  universal,  and  that  in  nebulous  and 
stellar  masses  we  may  expect  to  find  more  ele- 
mental forms  of  matter  than  are  known  on 
earth,  was  maintained  by  the  writer  in  May, 
1867.  In  August,  1874,  connecting  this  con- 
ception with  the  earlier  speculations  of  Dumas 
as  to  the  composite  nature  of  the  so-called 
chemical  elements,  and  with  the  order  of  ap- 
pearance of  these  in  different  classes  of  stars, 
as  noticed  by  Clarke,  it  was  suggested  that  the 
material  from  which  the  known  elements  have 
been  generated  by  the  stoichiogenic  process, 
through  successive  condensations  in  cooling,  is 
no  other  than  the  unknown  element  discerned 
by  the  spectroscope  in  the  solar  chromosphere, 
as  the  well  known  line,  1474.  These  views, 
which,  as  we  have  shown,  have  since  been  per- 


il 


1 


IP 


iil 


T-p^ 


36 


A  Chemical  Philosophy. 


sistently  and  repeatedly  asserted  by  the  writer, 
are  now  finding  recognition  among  chemisi 
some  of  whom  seem  to  overlook  the  history  oi 
their  origin.  Such  a  genesis  of  the  elements  is 
assumed  by  E.  J.  Mills,  who,  in  1886,  writes  :  ^ 
"  The  cooling  of  the  primitive  matter  may  be 
regarded  from  a  chemical  point  of  view  as 
resulting  in  a  succession  of  polymers  (i,  2, 
3  ...);/ ;  n  being  the  primitive  density. 
But,  on  account  of  the  evolution  of  heat  when 
a  polymer  is  formed,  there  will  ensue,  as  :• 
physical  consequence,  the  inversion  of  more 
less  of  the  cooling,  and  therefore  of  the  poly- 
merization "  ;  a  process  of  which  it  is  easy  to 
trace  the  history,  as  Mills  has  done,  in  variable 
stars. 

§  20.  In  his  address  before  the  British  Asso- 
ciation for  the  Advancement  of  Science,  in 
September,  1886,  Crookes  has  given  a  popular 
statement  of  the  hypothesis  of  the  genesis  of 
the  chemical  elements  from  an  intensely  heated 
primal  matter,  during  the  cooling  of  which  they 
have   been   formed    by   successive   polymeriza- 

1  Numerics  of  the  Elements,  Part  II.  L.,  E.,  and  D. 
Philos.  Mag.  xxi.  157. 


Genesis  of  the  Chemical  Elements.         37 

tions.  All  of  this  he  connects  with  Prout's 
hypothesis  of  atomic  weights,  and  suggests 
that  an  unknown  element  in  the  solar  atmos- 
phere may  be,  if  not  the  primal  matter,  a 
substance  having  one-half  the  weight  of  hydro- 
gen. I  had  already  in  1874  expressed  the 
opinion  that  this  substance  might  be  the  ele- 
ment giving  the  green  line,  1474,  of  Kirchhoff, 
so  conspicuous  in  the  corona  ;  of  which  Young  ^ 
remarks  that  it  would  seem  that  "it  must  be 
something  with  a  density  far  below  that  of 
hydrogen."  Crookes,  however,  now  suggests, 
in  1 886,  another  ^ement,  the  hypothetical 
helium  of  Franklanu,  which  gives  the  yellow 
line  D3.  Still  other  unknown  lines  have  of 
late  years  been  discovered  in  the  solar  spec- 
trum, all  of  which  may  correspond  to  so-called 
elemental  species  developed  by  the  stoichi- 
ogenic  process  ;  and  it  may  be  a  question  to 
which  the  primacy  should  be  conceded. 

1  C.  A.  Young,  The  Sun,  188 1 ;  p.  232. 


'li 


m 


f  '^!ii 


•'  'i 


■^ 


c 


■^i 


^m 


CHAPTER    IV. 

GASES,    LIQUIDS,    AND   SOLIDS. 

§  20.  After  noting,  in  1853,  that  the  equiva- 
lents for  volatile  bodies  are  fixed  from  their 
vapor-densities,  and  for  "  non-volatile  species  are 
generally  assumed  to  be  those  quantities  which 
sustain  the  simplest  ratio  to  certain  volatile 
ones,"  it  was  said  that,  "  having  determined  the 
true  equivalent  of  a  species  from  the  density  of 
its  vapor,  the  inquiry  arises  whether  a  definite 
and  constant  relation  may  not  be  discovered 
between  its  vapor-density  and  the  specific  grav- 
ity of  a  species  in  its  solid  state.  Such  a  rela- 
tion being  established,  and  the  value  of  the 
condensation  in  passing  from  a  gaFCOus  to 
a  solid  state  being  known,  the  equivalents  of 
solids,  like  tho5C  of  vapors,  might  be  deter- 
mined from  their  specific  gravities."  In  an- 
swer to  the  question  then  asked,  "  What  is  the 
value  of  the  condensation  which  takes  place  in 
the  change  from  the  gaseous  to  the  solid  state, 

38 


I 


Gases,  Liquids,  and  Solids, 


39 


or  what  equivalent  corresponds  to  a  given  spe- 
cific gravity  in  any  crystalline  solid  ? "  the  re- 
ceived formulas  for  alum,  ferrocyanid  of  potas- 
sium, and  glucose  were  discussed ;  and  it  was 
said  :  **  The  equivalent  of  a  crystallized  species 
may  often  be  a  multiple  of  that  deduced  from 
those  chemical  changes  which  commence  only 
with  the  destruction  of  its  crystalline  individu- 
ality." It  was  added:  "There  are  reasons  for 
believing  that  the  equivalents  of  these  species 
in  the  crystalline  state  correspond  to  some  mul- 
tiples of  the  above  formulas,  a  question  which 
is  to  be  decided  by  an  examination  of  the  crys- 
tallization and  the  specific  gravity  of  species 
whose  equivalents  are  admitted  to  be  higher." 
Farther,  it  was  said :  "  Favre  and  Silbcrmann 
from  their  researches  on  the  heat  evolved  in 
fusion  and  solution,  have  been  led  to  conckide, 
firstly,  that  crystallized  salts  arc  polymeric  of 
these  same  salts  in  solution  —  that  is,  they  are 
represented  by  formulas  which  are  multiples  of 
those  deduced  from  analysis ;  secondly,  that 
double  salts  and  acid  salts  do  not  exist  in  solu- 
tion, being  produced  only  during  crystalliza- 
tion ;  and,  thirdly,  that  water,  in  crystallizing, 


I    !  il 


40 


A  Chemical  Philosophy. 


changes  from  HO  to  «HO,  n  being  some 
whole  number.^  These  conclusions  are  seen  to 
be  in  accordance  with  those  deduced  from  a 
consideration  of  the  relations  of  density  and 
equivalent  volume.  A  polymerism  is  evident  in 
such  salts  as  sulphate  of  potash  and  cyanid  of 
potassium,  when  their  specific  gravities  are 
compared  with  those  of  alum  and  the  ferro- 
cyanid." 

§  21.  Passing  thence  to  the  consideration  of 
the  alcohols  and  their  derivatives,  it  was  re- 
marked that  several  of  those  then  known  "have 
very  nearly  the  same  specific  gravity,  so  that  the 
condensation  is  inversely  as  their  vapor-equiva- 
Icnts."  It  was  added  that,  in  a  farther  study 
of  such  bodies,  "  the  specific  gravity  at  their 
boiling-points  should  probably  be  chosen  for 
comparison,"  and  that  we  may  expect  to  "  es- 
tablish a  simple  relation  between  the  densities 
of  liquids  and  their  vapors."  (4.) 

§  22.  In  resuming  this  subject  in  1867,  it 
was  farther  said  :   "  There  probably  exists  be- 


'M 


Rccherches  sur  les  quantitds  de  chaleur  degagees  dans 
les  actions  chimiqucs  et  moleculaires.  1847.  Comptes  Rendus 
de  I'Acad.  des  Sciences,  xxiv.  1 081-1090. 


Gases f  Liquids,  and  Solids. 


41 


tween  the  true  equivalent  weights  of  non-gas- 
eous species  and  their  densities  a  relation  as 
simple  as  that  between  the  equivalent  weight 
of  gaseous  species  and  their  spec-nc  gravities." 
That  it  was  possible  to  discover  such  a  relation, 
had  already  been  maintained  in  1853,  when, 
as  we  have  seen,  the  doctrines  of  polymerism 
and  of  high  equivalent  weights  for  liquid  and 
solid  species  had  been  fully  set  forth.  The 
chemical  relation  between  solids,  liquids,  and 
gases  was  now,  however,  first  clearly  defined  as 
follows  : 

"The  gas  or  vapor  of  a  volatile  body  con- 
stitutes a  species  distinct  from  the  same  body 
in  its  liquid  or  solid  state,  the  chemical 
formula  of  the  latter  being  some  multiple  of 
the  first ;  and  the  liquid  and  solid  species  often 
[probably  always]  constitute  two  distinct  spe- 
cies, of  different  equivalent  weights.  In  the 
case  of  analogous  volatile  species,  as  the  hydro- 
carbons and  their  derivatives,  the  equivalent 
weights  of  the  liquid  and  solid  species  approxi- 
mate to  a  constant  quantity,  so  that  the  densi- 
ties of  those  species  in  the  case  of  homologous 
or  related  alcohols,  acids,  ethers,  and  glycerids, 


|i 


it-  i 


* 


Nij- 


jl  :: 


I 


42 


A  Chemical  Philosophy. 


are  subject  to  no  great  variations.  These 
non-gaseous  species  are  generated  by  the  chem- 
ical union  or  identification  of  a  number  of  vol- 
umes or  equivalents  of  the  gaseous  species, 
which  number  varies  inversely  as  the  density  of 
those  gaseous  species."  (10.) 

In  1874,  reverting  to  the  conception  of  the 
polymerism  exhibited  in  different  forms  of  car- 
bon and  phosphorus,  as  maintained  in  1848 
(page  12),  it  was  said:  "By  the  comparison  of 
these  with  substances  known  to  possess  a  high 
equivalent  weight,  as,  for  example,  some  organic 
bodies,  it  would  even  be  possible  to  fix  that  of 
these  elemental  species ;  which  would  certainly 
be  found  to  have  a  very  elevated  equivalent, 
indicating  a  high  degree  of  polymerism."  (12.) 


CHAPTER   V. 


THE    LAW    OF    NUMBERS. 


§  23.  The  law  of  numbers,  which  is  seen  in 
the  doctrine  of  multiple  proportions  and  in 
polymerism,  received  a  great  extension  in  the 
discovery  of  what  have  been  called  progressive 
series,  made  known  in  1842,  by  James  Schiel, 
and  adopted  by  Ch.  Gerhardt,  in  1844,  in  his 
Precis  de  Chimie  Organique,  under  the  name 
of  homologous  series.  This  conception  was  by 
these  chemists  applied  only  to  hydrocarbona- 
ceous  compounds,  differing  from  each  other  by 
C2H2,  which  was  shown  to  be  the  common  dif- 
ference in  the  formulas  of  certain  series  of 
bodies  having  similar  chemical  relations. 

As  regards  the  farther  extension  of  this  prin- 
ciple, and  the  breaking-down  of  the  distinction 
hitherto  maintained  between  so-called  organic 
chemistry  and  mineral  chemistry,  it  was  said 
by  the  writer,  in   1852,   that  "  wc  may  define 

43 


j, 

■ 

44 


A  Chemical  Philosophy. 


organic  chemistry  as  the  chemistry  of  the  com- 
pounds of  carbon."  These  were  then  spoken 
of  as  "  the  carbon  series  "  ;  while  "  the  silicon 
series "  was  made  to  include  all  the  known 
silicious  compounds.  (3.)  Of  the  above  defi- 
nition it  has  been  elsewhere  said  that,  "  though 
a  commonplace  to-day,  it  was,  perhaps,  then 
made  for  the  first  time."    (16.) 

(3.)  In  1853  it  was  farther  pointed  out  that 
"  C2H2  may  be  compared  with  O2H2  and  with 
O2M2"  (CH2,  OH2,  OM2,  in  the  present  notation); 
so  that  since  species  differing  by  //(CjHa)  may 
be  homologous,  "  it  may  be  expected  that  min- 
eral species  will  exhibit  the  same  relations  as 
those  of  the  carbon  series,  and  the  principle  of 
homology  be  greatly  extended  in  its  applica- 
tion," as  was  then  shown  by  reference  to  many 
silicates.  (4.)  In  the  same  year  it  was  also 
said  :  "  The  formulas  of  homologous  bodies  may 
be  represented  as  series  in  arithmetical  progres- 
sion [progressive  series].  The  first  term  may 
be  the  same  as  the  common  difference,"  as  in 
the  hydrocarbons  of  the  series  //(CHg),  or  un- 
like the  common  difference,  as  in  the  ammo- 
nias NH3.  .  .  .  NH3.«(CH2).     "Both  of  these 


The  Law  of  Numbers. 


45 


cases  are  illustrated  in  the  chemical  history  of 
mineral  species";  and  "M.^Sg,  M2O2,  and  HjOa 
may  be  compared  with  H^Ca."  The  application 
of  these  principles  was  then  shown  at  length. 
(5.)  The  members  of  a  progressive  series  in 
which  the  first  term  is  the  same  as  the  com- 
mon difference  may  be  designated  as  isomeric 
homologues  ;  while  all  other  progressive  series 
are  appropriately  called  anisomeric. 

§  24.  The  progressive  series  among  gaseous 
species,  except  in  some  few  hydrocarbons,  are 
examples  of  anisomeric  homologues.  To  these 
gaseous  species  belong  all  considerations  as 
to  metagenesis,  from  the  study  of  which  have 
grown  up  the  so-called  rational  and  structural 
formulas,  and  the  theory  of  types.  With  regard 
to  all  these  it  is  well  to  remember  "  the  lan- 
guage of  Ch.  Gerhardt,  that  they  '  are  not 
intended  to  represent  the  arrangement  of 
atoms,  but  to  make  evident,  in  the  simplest 
and  most  direct  manner,  the  relations  which 
connect  bodies  with  one  another  in  their  trans- 
formations.' This  understood,  and  with  these 
reservations,  they  have  an  important  place  in 
chemical  teaching."  (12.) 


.   s. 


m 


46 


A  Chemical  Philosophy. 


The  new  aspects  revealed  by  the  periodic 
law,  and  the  discovery  of  the  reciprocal  rela- 
tions between  the  properties  and  the  combining 
weights  of  the  elements  suffice  to  show  that  the 
hypothesis  of  Prout  must,  at  least,  be  greatly 
modified  before  it  can  be  received,  and  help, 
moreover,  to  give  a  more  profound  significance 
than  was  before  imagined  to  the  law  of  num- 
bers in  chemistry. 

In  1874  the  writer  noticed  the  variations  in 
composition  which  J.  P.  Cooke,  who  had  ob- 
served them  in  certain  alloys,  described  under 
the  name  of  allomerism.  These  alloys  were 
then  regarded  as  "examples  of  a  progressive 
series  of  isomorphous  compounds  of  antimony 
and  zinc,  of  high  equivalent,  differing  from 
each  other  by  nZu^^  '  The  bearing  of  this 
conception  on  the  recent  views  of  Boutlerovv 
and  Schiitzenbergcr  as  to  the  apparent  varia- 
bility of  the  law  of  definite  proportions,  and 
on  Cooke's  discussion  thereof,^  is  evident. 

'  Hunt,  Chemical  and  Geological  Essays,  p.  447. 
2  American  Journal  of  Science  (1S83),  xxvi.  63,  310. 


CHAPTER  VI. 


EQUIVALENT   WEIGHTS. 


§  25.  The  conception  of  high  equivalent 
weights  for  liquid  and  solid  species,  already 
indicated  in  the  extracts  in  §§  20-22,  was  illus- 
trated at  length  in  1853  and  1854,  when  the 
carbon-spars  were  represented  in  formulas  as 
polycarbonates  with  from  thirty  to  forty  por- 
tions of  carbon  (C  =  6)  ;  and  the  pyroxenes, 
amphiboles,  and  feldspars  as  polysilicates  with 
from  thirty-two  to  sixty  portions  of  silicon 
(Si  =  7).  The  equivalent  weights  thus  provis- 
ionally adopted  for  these  species  were  con- 
fessedly minima;  and  their  relations  to  the 
higher  numbers  of  which  they  were  supposed 
to  be  fractions  were  left  undetermined.  (5,  6.) 
Of  these  elevated  equivalent  weights  and  com- 
plex formulas  it  was  subsequently  declared  that 
they  do  not  show  "  a  deviation  from  the  law  of 
definite  proportions,"  but  are  "  only  an  expres- 
sion of  that  law  in  a  higher  form."  (10.) 

47 


1! 

f  i  :i  n  f 


.'  f'  I 


i 


A  Chemical  Philosophy. 


^   m 


m 


§  26.  Reverting,  in  this  connection,  to  what 
has  been  said  in  §  22,  we  repeat,  that  all  liquid 
and  solid  species,  so  far  as  known,  may  be 
represented  as  polymers  of  some  primary  spe- 
cies or  chemical  unit.  The  minimum  equiva- 
lent weights  of  these  chemical  units,  which,  by 
their  polymerism,  give  rise  to  higher  species, 
must  often  of  necessity  be  considerable,  as  in 
the  case  of  many  of  the  aniline  derivatives,  the 
ammonio-cobalt  compounds,  and  the  polytung- 
states.  Wolcott  Gibbs,  who  shows  that  these 
latter  constitute  progressive  series,  finds  the 
common  difference,  which  he  terms  the  "  ho- 
mologizing  term,"  in  the  phosphotungstates  is 
not  less  than  2(W03=  464),  and  shows  for 
these  heavy  polytungstates  equivalent  weights, 
not  only  of  5002,  but,  in  one  case,  of  20,058  ; 
while  for  the  less  heavy  ammonio-cobalt  salts 
minimum  equivalent  weights  of  from  500  to 
2500  are  deduced.  Even  these  elevated  num- 
bers, as  we  shall  endeavor  to  show,  are  but 
fractions  of  the  true  equivalents  of  the  crystal- 
line polymeric  solids,  which,  for  the  species 
under  consideration,  vary  from  about  50,000  to 
more  than  220,000. 


Equivalent  Weights. 


49 


§  27.  The  proofs  which  careful  analytical 
studies  have  afforded  of  the  necessarily  high 
equivalent  weights  and  the  complex  formulas  of 
the  polytungstates,  polymolybdates,  polyvana- 
dates,  and  polyphosphates,  led  Wolcott  Gibbs, 
in  1877,  to  designate  them  as  salts  of  "complex 
inorganic  acids,"  which,  according  to  him, 
"form  a  new  department  of  inorganic  chem- 
istry." It  will  be  remembered  that  I  had 
already,  in  1853,  proclaimed  that  the  whole 
chemistry  of  solids  and  liquids  is  only  intelligi- 
ble when  regarded  as  a  history  of  just  such 
complex  inorganic  acids  and  salts ;  that  the 
distinction  between  organic  and  inorganic 
chemistry  is  no  longer  tenable ;  that  the 
same  principles  of  homology  and  polymerism 
are  applicable  alike  to  the  bodies  of  the  car- 
bon series  and  the  silicon  series ;  that  the 
native  crystalline  carbonates,  or  carbon-spars, 
are  polycarbonates,  with  equivalent  weights 
of  not  less  than  from  1500  to  2500;  that  the 
pyroxenes,  feldspars,  and  tourmalines  are  poly- 
silicates  of  equally  complex  constitution,  and 
are  represented   by  formulas  which    show  the 

1  American  Journal  of  Science,  1877  ;  xiv.,  61. 


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A  Chemical  Philosophy. 


existence  among  them  both  of  polymers,  prob- 
ably homologous,  and  of  anisomcric  homo- 
logucs.  These  conceptions,  all  of  which  were 
explicitly  set  forth  and  defended  in  1852 
and  1853,  underlie  the  writer's  philosophy  of 
the  mineral  kingdom,  as  then  enunciated,  and 
as  persistently  maintained  to  the  present  date. 
The  inquiry  as  to  the  value  of  the  unit  in  these 
polymers,  and  of  the  common  difference  be- 
tween the  successive  members  of  these  homolo- 
gous series  of  polycarbonates  and  polysilicates 
—  whether  it  be  the  simplest  admissible  chemi- 
cal unit,  or  some  multiple  thereof  —  is  one 
which  will  be  considered  in  Chapter  XI. 


fr 


CHAPTER   VII. 

HARDNESS   AND   CHEMICAL    INDIFFERENCE. 

§  28.  That  the  specific  gravity  of  solids,  lilce 
that  of  gases  and  vapors,  varies  as  their  equiv- 
alent weights,  will  follow  from  the  principle, 
already  laid  down  in  1853,  that  chemical  union 
is  essentially  an  identification  of  volumes  ;  or, 
in  other  words,  a  condensation  of  many  vol- 
umes into  one.  The  farther  and  very  rational 
deduction  from  this  principle,  that  the  property 
of  hardness  in  similarly  constituted  species,  as 
well  as  their  resistance  to  chemical  agents, 
sustains  a  direct  relation  to  the  condensation, 
was  first  indicated  in  a  paper  by  the  writer, 
on  Euphotide  and  Saussurite,  in  the  American 
Journal  of  Science  for  1859,  wherein  were  dis- 
cussed the  physical  and  chemical  differences  of 
the  related  silicates,  meionite  and  zoisite.  In 
referring  to  this  in  a  note,  "  Sur  la  Nature  du 
Jade,"  presented   to   the   French  Academy  of 

3» 


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52 


A  Chemical  Philosophy. 


Sciences  in  June,  1863,  it  was  said,  in  compar- 
ing meionite  and  zoisite :  "The  augmentation 
of  density,  of  hardness,  and  of  chemical  indif- 
ference which  is  seen  in  this  last  species  is 
doubtless  to  be  ascribed  to  a  more  elevated 
equivalent  ;  or,  in  other  words,  to  a  more  con- 
densed molecule.^  These  different  degrees  of 
condensation,  which  are  constantly  kept  in 
mind  in  the  study  of  organic  chemistry,  are 
besides,  as  I  have  already  elsewhere  shown,  of 
great  importance  in  mineralogy,  and  will  form 
the  basis  of  a  new  system  of  classification, 
which  will  be  at  once  chemical  and  natural- 
historical.  The  different  rhombohedral  carbon- 
spars,  cyanite  and  sillimanite,  hornblende  and 
pyroxene,  offer,  in  like  manner,  examples  of 
different  degrees  of  condensation,  and,  by 
their  chemical  composition,  belong  to  series 
the  terms  of  which,  like  those  of  the  hydro- 
carbons—  //(CoHo)  —  are  both  homologues  and 

^  Regarding  the  relations  between  meionite  and  zoisite  it  was 
said:  " L'augmentation  de  densite,  de  diirete,  ct  d'indifference 
chimique  qu'on  remarque  dans  cette  derniere  espece  tient  sans 
doute  \  un  equivalent  plus  elev^,  c'est  i  dire  k  une  molecule 
plus  condensee."  Comptes  Rendus  de  I'Academie  des  Sciences, 
1863,  Ivi.  1256. 


Hardness  and  Chemical  Indifference.        5; 


multiples  of  the  first  term.  At  the  same 
time,  each  one  of  these  silicates  and  carbonates 
belongs  to  another  possible  series,  the  terms 
of  which  differ  by  //(MgOi),  corresponding  to 
more  or  less  basic  salts."    (9.) 

§  29.  These  relations  of  physical  and  chem- 
ical characters  to  condensation  were  again 
affirmed  in  1867,  when,  after  insisting  on  the 
evidences  of  polymerism  "  in  related  mineral 
species,  such  as  meionite  and  zoisitc,  dipyre 
and  jadeite,  hornblende  '  nd  pyroxene,  calcite 
and  aragonite,  opal  and  quartz,  in  the  zircons 
of  differci;::  densities,  and  in  the  various  forms 
of  titanic  oxyd  and  of  carbon,"  it  was  said : 
"The  hardness  of  these  isomeric  or  allotropic 
species,  and  their  indifference  to  chemical  re- 
agents increase  with  their  condensation ;  or,  in 
other  words,  vary  inversely  as  their  empirical 
equivalent  volumes,  so  that  we  here  find  a 
direct  relation  between  chemical  and  physical 
properties."  (10.) 

§  30.  The  same  relation  of  hardness  to 
condensation  is  evident  throughout  natural 
silicates,  and  underlies  the  great  distinction 
made    in    the    mineralogical    classification    of 


\ 


54 


A  Chemical  Philosophy. 


Mohs  between  the  order  Gem,  on  the  one  hand, 
and  the  order  Spar,  on  the  other.  This  distinc- 
tion is  made  still  more  apparent  in  the  division 
which  I  have  made  the  ground  of  tribal  sub- 
divisions running  through  the  three  sub-orders 
of  silicates,  and  in  each  separating  them  into 
the  gem-like  or  adamantoid  type,  on  the  one 
hand,  and  the  spathoid  and  hydrospathoid  types, 
on  the  other.  Passing  from  these  three,  which 
are  all  alike  essentially  sparry  in  crystalline 
structure,  to  the  phylloid  or  micaceous  type, 
the  significance  of  the  varying  condensation  in 
species  of  this  type,  as  regards  hardness,  is 
somewhat  obscured  by  the  eminent  cleavage 
in  one  plane.  The  same  is  true,  for  an- 
other reason,  in  the  colloid,  vitreous,  or  poro- 
dic  type  ^  {Porodini  of  Breithaupt),  the  species 


'  The  term  porodic  (German  porodisch),  from  the  Greek 
7Ku()6u),  to  harden,  coagulate,  or  make  callous,  was  proposed  by 
Breithaupt,  in  1836  (Handbuch  der  Mineralogie,  I.  324),  as 
synonymous  with  the  German  geronnen  (curdled  or  clotted),  to 
designate  amorphous,  opal-like,  gelatinous,  or  vitreous  bodies, 
destitute  of  cleavage  or  other  marks  of  crystalline  structure ; 
and  corresponds  to  the  term  colloid,  subsequently  devised  by 
Graham.  Among  Dorodic  species  Breithaupt  included,  be- 
sides colloidal  su)i-...»tes,  phosphates,  and  arsenates,  such 
bodies  as  opal,  serpentine,  chrysocoUa,  allophane,  tachylite, 


Hardness  and  CJiemical  Indifference.       55 

of  which  —  in  many  cases,'  at  least  —  include 
crystalline  portions  belonging  to  sparry  types. 
The  tribal  distinctions  above  indicated  are 
farther  noticed  in  §  32. 

A  similar  relation  between  hardness  and 
chemical  indifference  and  the  degree  of  con- 
densation has  also  been  pointed  out  by  the 
author  for  the  anhydrous  oxyds  other  than 
silicates,  and  for  metals  and  their  compounds 
with  sulphur,  selenium,  tellurium,  arsenic,  and 
antimony,  which  make  up  the  several  tribes  of 
the  sub-orders  Metallometallate  and  Spatho- 
metallate  in  the  great  natural  order  of  the 
Metallates.    (16.) 

§  31.  The  question  of  the  relations  of  chem- 
ical indifference  to  condensation  has  lately 
received  a  new  and  important  illustration  from 
the  study  of  the  silicates.  That,  while  many  of 
these  are  readily  attacked  by  fluorhydric  acid, 
some  few  of  them  resist  more  or  less  com- 
pletely   its    action,    has     long     been     known. 

and  obsidian  —  substances  alike  of  aqueous  and  of  igneous 
origin.  Besides  an  order,  Porodini,  he  subsccjuently  defined 
porodic  genera  in  other  orders.  See,  farther,  the  author's 
Mineral  Physiology  and  Physiography,  p.  383. 


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A  CJicmical  Philosophy. 


Among  the  latter  had  been  noticed  staurolite 
and  zircon,  and,  more  recently,  amphibole,  pyrox- 
ene, and  chrysolite,  —  a  fact  of  which  Fouquc 
availed  himself  to  separate  the  last  two  spe- 
cies from  various  feldspars  and  from  vitreous 
silicates.  Mr.  J.  B.  Mackintosh,  late  of  Colum- 
bia College,  New  York,  and  now  of  Lehigh 
University,  in  extending  these  observations, 
found,  as  he  informed  mc,  a  few  months  since, 
that  garnet  also  is  indifferent  to  the  action  of 
the  acid  ;  a  fact  ascribed  by  me  to  its  great 
condensation,  which  I  had  already  concluded 
to  be  the  cause  of  the  similar  indifference  of 
the  species  above  named.  In  confirmation  of 
this  view  I  suggested  a  comparison  between 
the  more  condensed  species  epidote  and  spod- 
umene,  on  the  one  hand,  and  the  less  con- 
densed iolite  and  petalite,  on  the  other ;  pre- 
dicting the  insolubility  of  the  first  two  and  the 
solubility  of  the  last  two  in  fluorhydric  acid. 
This  prevision  was  at  once  confirmed  by 
Mackintosh,  who  has  since  greatly  extended, 
and  made  quantitative,  similar  experiments  on 
many  of  the  more  important  silicates. 

§  32.  In  an  attempt  at  A  Natural  System  in 


Hardness  and  Chemical  Indifference.        57 


11 

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Mineralogy,  in  1885  (16),  there  was  proposed, 
as  already  noticed,  for  the  three  sub-orders  into 
which  the  order  of  Silicates  was  divided,  a 
classification  into  tribes,  based  in  great  part  on 
the  different  degrees  of  condensation  ;,  and  it 
may  be  said,  in  a  few  words,  that  the  results  of 
Mackintosh  appear  in  all  cases  to  verify  the 
law  of  chemical  indifference  laid  down  in  1863. 
While  the  Pectolitoids,  including  pectolite, 
apophyllite,  and  calamine;  the  Protospathoids, 
like  willemite  and  wollastonite;  the  Zeolitoids; 
and  the  various  Protoperspathoids,  including 
the  feldspars,  scapolites,  leucite,  iolite,  and 
petalite,  are  more  or  less  completely  attacked 
and  dissolved  by  fluorhydric  acid,  the  Protada- 
mantoids,  like  pyroxene,  amphibole,  and  chryso- 
lite, resist  more  or  less  completely  its  action* 
To  this  tribe,  also,  rather  than  to  the  Pectoli- 
toids, datolitc,  from  its  great  condensation  and 
its  comparative  indifference  to  the  acid  solvent, 
appears  to  belong.  The  same  indifference  is 
observed  in  the  Protoperadamantoids,  including 
garnet,  epidote,  zoisite,  axinite,  spodumcne, 
staurolitc,  and  the  tourmalines,  besides  ido- 
crase  and  prchnite.     In  like  manner,  the  Perad- 


;8 


A  Chemical  Philosophy. 


i 

:  1 

*  i 

amantoids  andalusite,  topaz,  and  cyanite  resist 
its  action.  Among  the  phylloid  or  micaceous 
silicates,  which  are,  for  the  most  part,  though 
less  hard  than  spathoids,  highly  condensed 
species,  the  Protophylloid  talc,  and  the  Proto- 
perphylloids  ripidolite,  margarite,  zinnwaldite, 
and  muscovite  resist  the  action  of  the  acid ; 
while  biotite,  phlogopite,  and  jefferisite  are  but 
slightly  attacked. 

§  33.  The  rate  of  attack  under  similar  condi- 
tions varies  greatly  for  different  species.  When 
a  given  weight  of  the  mineral  in  grains  of  a 
determined  size  is  exposed  for  an  hour  to  a 
large  excess  of  a  dilute  fluorhydric  acid  which 
fails  to  attack  sensibly  the  more  resisting  sili- 
cates, Mackintosh  finds  that,  in  round  numbers, 
from  one  to  two  per  cent  of  amphibole,  about 
five  of  chrysolite,  from  twenty-five  to  thirty-five 
of  petalite,  and  the  feldspars,  albite,  oligoclase, 
and  labradorite,  forty-three  of  orthoclase,  and 
sixty-six  of  leucite  are  dissolved ;  while  willem- 
ite,  like  the  colloid  species  halloysite,  is  com- 
pletely dissolved.  The  same  is  true  of  the  col- 
loid, opal,  while  artificial  tridymite  is  also 
readily  attacked,  but  quartz  is  more  resisting 


Hardness  and  Chemical  Indifference.        59 

than  chrysolite.  In  experiments  on  a  blast- 
furnace slag,  it  was  found  that  portions  of  the 
mass,  which,  on  slow  cooling,  had  passed  from  a 
vitreous  or  porodic  condition  to  one  of  crystal- 
linity,  with  a  notable  increase  in  density,  had 
become  much  less  soluble  in  the  acid.  The 
publication  of  the  farther  results  of  these  stud- 
ies, which  are  still  in  progress,  and  which  Mack- 
intosh has  kindly  communicated  to  me,  will 
constitute  a  most  important  contribution  to 
chemical  mineralogy,*  and  a  farther  proof  of  the 
dependence  of  chemical  indifference  on  conden- 
sation. 

1  They  have  as  yet  been  made  known  only  by  preliminary 
notices,  —  in  the  School  of  Mines  Quarterly,  in  July,  1S86; 
in  a  paper  by  me,  as  yet  unpublished,  read  to  the  Roval 
Society  of  Canada,  May  26,  1S86;  and  in  an  appendix  to  my 
recently  published  Mineral  Physiology  and  Physiography.  A 
more  complete  account,  entitled  "  The  Action  of  Hydrofluoric 
Acid  on  Silica  and  the  Silicates,"  was  read  by  Mackintosh  be- 
fore the  American  Chemical  Society,  in  New  York,  November 
5, 1886,  and  appears  in  the  new  Journal  of  Analytical  Chem- 
istry for  January,  18S7. 


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CHAPTER  VIII. 


THE   ATOMIC    HYPOTHESIS. 


§  34.  From  an  early  time  in  the  history  of 
thought  two  distinct  and  opposite  conceptions 
of  the  intimate  nature  of  matter  have  had  their 
partisans.  The  Pythagoreans  taught  the  infi- 
nite divisibility  of  matter,  and  its  continuity  in 
a  given  mass,  —  a  view  held  by  Plato  and  Aris- 
totle, and  by  Kant  among  modern  masters. 
The  opposed  doctrine  of  the  finite  divisibility 
of  matter,  and  the  existence  of  ultimate  mate- 
rial particles,  or  atoms,  taught  by  Leucippus, 
can  be  traced  to  Phoenician,  Hindoo,  and,  prob- 
ably, to  Egyptian  sources.  It  was  maintained 
by  Epicurus  and  his  school,  was  lauded  by 
Francis  Bacon,  and  adopted  by  Newton,  though 
controverted  by  Descartes,  Leibnitz,  and  Euler ; 
and  had  fallen  into  neglect  until  resuscitated  in 
this  century  by  Dalton,  in  his  System  of  Chemi- 

60 


The  Atomic  Hypothesis. 


6i 


cal  Philosophy,  published  in  i8oS  ;  since  which 
time  it  has  been  accepted  by  most  of  the  popu- 
lar writers  on  chemistry  as  a  necessary  part  of 
the  law  of  definite  and  multiple  proportions 
then  unfolded  by  Dalton.^  The  kinetic  hypoth- 
esis of  the  constitution  of  gases,  which  con- 
ceives them  to  consist  of  solid,  perfectly  elastic 
spherical  particles,  moving  in  all  directions, 
and  actuated  with  different  degrees  of  velocity 
for  different  gases,  first  put  forward  by  D.  Ber- 
noulli, in   1747,  and  adopted  by  many  modern 

1  See,  for  a  history  of  the  atomic  hypothesis,  Daubeny, 
Introduction  to  the  Atomic  Theory,  and,  more  concisely, 
Odling,  Watts's  Dictionary  of  Chemistry,  under  "  Atomic 
Weights."  Also  for  an  extended  discussion  of  the  history  of 
the  atomic  hypothesis,  and  the  arguments  for  and  against  it, 
Whewell,  History  of  the  Inductive  Sciences,  vol.  i.  book  vi. 
chap.  5.  He  there  declares  that  its  doctrines,  when  they  "  are 
tried  upon  the  general  range  of  chemical  observation,  prove 
incapable  of  even  expressing,  without  self-contradiction,  the 
laws  of  phenomena."  "  Chemical  facts  not  only  do  not  prove 
the  atomic  theory  as  a  physical  truth,  but  they  are  not,  accord- 
ing to  any  modification  yet  devised  of  the  theory,  reconcilable 
with  its  scheme."  He  adds  that  "  when  we  would  assert  this 
theory,  not  as  a  convenient  hypothesis  for  the  expression  or 
calculation  of  the  laws  of  nature,  but  as  a  philosophical  truth 
respecting  the  constitution  of  the  universe,  we  find  ourselves 
checked  by  difiiculties  of  reasoning  which  we  cannot  overcome, 
as  well  as  by  conflicting  phenomena  which  we  cannot  reconcile." 


!  V.  ■  I 


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62 


A  Chemical  Philosophy. 


^ 


in 


physicists,  was,  according  to  Graham,  resusci- 
tated in  our  own  time  by  Herepath,  in  1847.^ 

§  35.  In  discussing,  in  1853,  the  nature  of 
the  chemical  process,  as  already  set  forth  in 
Chapter  II.,  it  was  asserted  that,  "as  chemical 
combination  is  not  a  putting  together  of  mole- 
cules, but  an  interpenetration  of  masses,  the  ap- 
plication of  the  atomic  hypothesis  to  explain  the 
law  of  definite  proportions  is  wholly  unneces- 
sary." (4.)  Again,  it  was  said  that,  since  "  the 
volumes  of  the  uniting  species  are  always  merged 
in  that  of  the  new  one  .  .  .  the  atomic  theory, 
as  applied  by  Dalton,  which  nakes  combination 
consist  in  juxtaposition,  is  ULcCnable."  (5.) 

§  36.  "  If,  then,  as  maintained  by  the  writer, 
the  law  of  volumes  is  universal,  and  if  the 
production  of  liquids  and  solids  by  the  con- 
densation of  vapors  is  a  process  of  chemical 
union  or  integration,  giving  rise  to  polymers 
the  equivalent  weights  of  which  are  as  much 
more  elevated  as  their  densities  are  greater 
than    those    of  the  vapors  which   combine   to 

1  Graham,  Chemical  and  Physical  Researches,  p.  211,  note. 
For  a  critical  examination  of  this  hypothesis,  see  Stallo,  The 
Concepts  and  Theories  of  Modern  Physics,  chapters  iv.  vii.  viii. 


The  Atomic  Hypothesis, 


63 


pl' 

Jill 

form  them,  the  application  of  the  hypothesis  of 
atoms  and  molecules  to  explain  the  law  of 
definite  proportions  and  the  chemical  process 
is  not  only  unnecessary  but  misleading.  Ac- 
cording to  this  hypothesis,  which  supposes 
molecules  to  be  built  up  of  atoms,  and  masses 
of  molecules,  the  different  ratios  in  unlike 
species  between  the  combining  weight  of  the 
chemical  unit,  or  molecule  (as  deduced  from 
analysis  and  from  vapor-density,  H  =  i.o), 
and  the  specific  gravity  of  the  mass  are  sup- 
posed to  represent  the  relative  dimensions  of 
the  molecules.  Hence,  the  values  got  for  sol- 
ids and  liquids  by  dividing  these  combining 
weights  by  the  specific  gravity  have  been 
called  'molecular  volumes.'  The  number  of 
such  *  chemical  molecules,'  required  to  build  up 
a  *  physical  molecule '  of  constant  volume 
would,  according  to  this  hypothesis,  be  in- 
versely as  their  size.  If,  however,  as  all  the 
phenomena  of  chemistry  show,  the  formation  of 
higher  and  more  complex  species  is  by  conden- 
sation or  integration,  or,  in  other  words,  by 
identification  of  volume,  and  not  by  juxtaposi- 
tion, it  if     ws  that  the  so-called  molecular  vol- 


ifl 


64 


A  Chemical  Philosophy. 


■"  5f '  I 


umes  arc  really  numbers  representing  the  rela. 
tive  amounts  of  contraction  of  the  respective 
substances  in  passing  from  the  gaseous  to  the 
liquid  or  solid  state,  and  are  the  reciprocals  of 
the  coefficient  of  condensation  of  the  assumed 
chemical  units,"  or  atoms,  or  molecules.^  (17.) 

§  37,  Hence  it  was,  that  in  discussing,  in 
1885,  the  relations  of  density  to  equivalent, 
while  we  admitted  the  language  of  the  atomic 
hypothesis,  and,  in  making  use  of  the  well 
known  formula  / -t- <^/:=  7',  recognized  chemical 
units  or  molecules,  whose  equivalent  or  combin- 
ing weights  are  represented  by/,  we  were  care- 
ful to  say  that  differences  in  the  density  of 
solid  species  "  are  not  dependent  on  variations 
in  the  hypothetical  units  adopted  for  conven- 
ience in  calculation,  but  belong  to  the  species 
as  an  integer,  and  correspond  to  a  greater  or 
less  condensation  of  its  mass ;  that  is  to  say,  to 
the  identification  in  a  constant  volume  of  a 
greater  or  less  number  of  these  chemical  units. 
The  very  terms  of  atom  and  molecule  which 


1  The  paper  here  quoted,  on  "The  Law  of  Volumes  in 
Chemistry,"  is  reprinted  in  the  Chemical  News  for  October 
26,  1886. 


The  Atomic  Hypothesis. 


65 


we  apply  to  these  imaginary  units,  and  to  the 
mass,  are  concessions  to  a  popular  terminology, 
and  are  not  only  inadequate  but,  to  a  certain 
extent,  misleading  when  applied  to  chemical 
operations."  (16.) 

§  38.  The  confusion  which,  as  already  pointed 
out  (§  11),  exists  in  the  minds  of  many  chemists 
between  dynamical  and  chemical  activities,  and 
prevents  a  clear  conception  of  the  nature  of  the 
chemical  process,  has  led  to  the  transference 
of  the  atomic  or  molecular  hypothesis  from  the 
theory  of  dynamics  to  the  theory  of  chemistry. 
The  phenomena  of  elasticity,  of  the  movements 
of  gases  and  liquids,  of  temperature,  of  elec- 
tricity, and  of  radiant  energy,  —  in  a  word,  all 
the  manifestations  which  come  under  the  head 
of  dynamics,  —  are,  in  the  opinion  of  many  of 
their  students,  most  easily  explained  if  we  sup- 
pose that  the  species  which  is  the  subject  of 
these  phenomena  has  a  structure,  not  continu- 
ous, but  made  up  of  discrete  molecules  or  atoms 
of  a  definite  and  constant  size,  which  in  liquid 
and  solid  bodies  varies  for  different  species. 

§  39.  The  acceptance  of  this  hypothesis  of 
the    constitution    of    matter    for    all    species, 


I 


66 


A  Chemical  Philosop/iy. 


whether  solid,  liquid,  or  gaseous,  will  be  seen,  on 
reflection,  to  have  no  direct  bearing  on  chemism ; 
which  does  not  consider  the  species  as  such,  but 
only  its  relations  to  the  species  from  which  it 
has  been  derived,  or  into  which  it  may  pass,  by 
processes  of  specific  integration  or  disintegra- 
tion, either  homogeneous  or  heterogeneous. 

If  it  were  possible  to  demonstrate  the  exist- 
ence of  a  molecular  structure,  for  example,  in  a 
crystal  of  calcite ;  to  fix,  as  has  been  attempted, 
by  calculation,  the  dimensions  and  the  weight 
of  the  constituent  molecules  by  the  juxtaposi- 
tion of  which  the  crystal  is  built  up,  we  should 
have  no  better  warrant  than  before  for  the 
hypothesis  that,  in  these  molecules  of  cclcite, 
either  the  unlike  chemical  species  of  carbonic 
dioxyd  and  of  calcic  oxyd,  or  those  others,  car- 
bon, calcium,  and  oxygen,  into  which  chemical 
disintegration  can  resolve  the  calcite,  are  pres- 
ent as  such.  "  Of  the  relations  which  subsist 
between  the  higher  species  and  those  derived 
from  them  we  can  only  assert  the  possibility, 
and,  under  certain  conditions,  the  certainty  of 
producing  the  one  from  the  other."  (4.) 

In    . jnsidering  this  subject  in   1874  it  was 


The  Atomic  Hypothesis. 


67 


said:  "Are  we  not  going  beyond  the  limits  of 
a  sound  philosophy  when  we  endeavor  by 
hypotheses  of  hard  particles  with  void  spaces, 
of  atoms  and  molecules  with  bonds  and  links, 
to  explain  chemical  affinities ;  and  when  we 
give  a  concrete  form  to  our  mechanical  concep- 
tions of  the  great  laws  of  definite  and  multiple 
proportions  to  which  the  chemical  process  is 
subordinated  ?  Let  us  not  confound  the  image 
with  the  thing  itself,  until,  in  the  language  of 
Brodie,  in  the  discussion  of  this  very  question, 
*  we  mistake  the  suggestions  of  fancy  for  the 
reality  of  nature,  and  cease  to  distinguish  be- 
tween conjecture  and  fact.'  The  atomic  hy- 
pothesis, by  the  aid  of  which  Dalton  sought  to 
explain  his  great  generalizations,  has  done  good 
service  in  chemistry,  as  the  Newtonian  theory 
of  light  did  in  optics,  but  is  already  losing  its 
hold  on  many  advanced  thinkers  in  our  sci- 
ence," (12.)' 

1  The  reader  may  ron'^ult  with  much  advantage,  in  this  con- 
nection, a  paper  by  C.  R.  A.  Wright,  On  the  Relations  between 
the  Atomic  Hypothesis  and  the  Condensed  Symbolic  Expres- 
sions of  Chemical  Facts  and  Changes  known  as  Dissected 
(Structural)  Fornuilae,  in  1872,  L.,  E.,  and  D.  Philos.  Mag. 
(4)  xliii.  241-264.  See,  also,  for  R,  A.  Atkinson's  strictures 
thereon,  and  Dr.  Wright's  rejoinder,  ibid.,  428-433,  503-514. 


f 

i, 

1    !■  ■ 

1-    i    . 

■    i  ' 

CHAPTER   IX. 


THE   LAW   OF   VOLUMES. 


§  40.  "  The  quantitative  relation  of  one  min- 
eral (chemical)  species  to  another  is  its  equiva- 
lent weight."  (10.)  As  regards  the  relation  of 
weight  to  volume,  it  was  said,  in  1853:  "The 
weights  of  equal  volumes  of  gases  and  vapors 
are  their  equivalent  weights ;  and  the  doctrine 
of  chemical  equivalents  is  that  of  the  equiva- 
lency of  volumes.  According  to  the  atomic 
hypothesis,  these  weights  represent  the  relative 
weights  of  the  atoms  ;  and,  as  equal  volumes 
contain  the  same  number  of  atoms,  these  must 
have  similar  volumes,  so  that  we  come  at  last 
to  the  equiva'oncy  of  volumes."  The  conden- 
sation which  constitutes  polymcrism  "  evidently 
offers  no  exception  to  the  law  of  equivalent  vol- 
umes." (4.)  Dalton,  in  his  remarkable  generali- 
zations, which  are  summed  up  in  his  theory  of 

definite  and  multiple  proportions,  '*  linked   his 

68 


mm 


The  Law  of  Vohmies. 


69 


discoveries  with  the  old  hypothesis  of  the 
atomic  constitution  of  matter,  which  is,  how- 
ever, by  no  means  necessarily  connected  with 
the  great  laws  of  combination  by  weight  and  by 
number.  It  was  reserved  for  Gay  Lussac  ^  to 
make  known  a  not  less  beautitui  generalization, 
by  showing  that  in  the  combination  of  vapors 
and  gases  there  exists  an  equally  simple  rela- 
tion of  volumes,  and  that  measure,  not  less 
than  number  and  weight,  governs  all  chemical 
changes."  "All  things,  declares  the  sage,^  are 
ordered  by  measure,  by  number,  and  by 
weight."  (12.)  Already,  in  1853,  it  had  been 
said  :  "  The  simple  relations  of  volume,  which 
Gay  Lussac  pointed  out  in  the  chemical 
changes  of  gases,  apply  to  all  liquid  and  solid 
species,    thus   leading   the   way   to    a    correct 


* 


'  In  his  Theory  of  Volumes,  Memoires  d'Arceuil,  1809, 
ii.  207. 

2  This  is,  of  course,  a  free  reading  of  the  passage  which 
we  have  chosen  fur  the  motto  of  this  volume :  "  Omnia 
mensura,  et  numero,  et  pondere  disposuisti,"  Liber  Sapientiae, 
cap.  xi.,  translated  in  the  received  English  version  of  the 
Bible:  "Thou  hast  ordered  all  things  in  measure,  and  num- 
ber, and  weight,"  Wisdom,  xi.  20.  The  Greek  original  of 
this  is  made  by  Daubcny  the  epigraph  to  his  Introduction  to 
the  Atomic  Theory. 


m 


70 


A  Chemical  Philosophy. 


understanding   of    the   equivalent  volumes    of 
the  latter."  (5.) 

§  41.  We  had  thus  in  the  development  of  a 
theory  of  chemistry  clearly  defined  the  princi- 
ple that  the  doctrine  of  chemical  equivalents  is 
that  of  the  equivalency  of  volumes;  and  that 
the  law  of  volumes  is  univen^al,  and  applies  not 
only  to  gases  but  to  liquids  and  solids,  which 
are  species  distinct  from  their  corresponding 
vapors.  We  had,  moreover,  already,  in  1853, 
inquired  **  whether  a  definite  and  constant  rela- 
tion may  not  be  discovered  between  its  vapor- 
density  and  the  specific  gravity  of  a  species  in 
its  solid  state,"  and  had  asked  "what  equiva- 
lent corresponds  to  a  given  specific  gravity  in 
any  crystalline  solid ;  or,  in  other  words,  what 
is  the  value  of  the  condensation  which  takes 
place  in  the  change  from  the  gaseous  to  the 
solid  state  t "  It  was  farther  said  :  "  Such  a 
relation  being  established,  and  the  value  of  the 
condensation  in  passing  from  a  gaseous  to  a 
solid  state  being  known,  the  equivalents  of 
solids,  like  those  of  gases,  might  be  determined 
from  their  specific  gravities."  (4.)  It  remains 
to  be  shown  why  the  solution  of  the  problem^ 


The  Law  of  Volumes. 


71 


now  offered  for  the  first  time  in  1886,  which 
seems  an  obvious  deduction  from  the  principles 
thus  laid  down  in  1853,  was  not  sooner  dis- 
covered. 

§  42.  The  explanation  is  to  be  found  in  the 
fact  that,  while  affirming  in  a  broader  sense 
than  had  before  been  stated  the  universality 
of  the  law  of  volumes,  the  writer  still  believed, 
in  accordance  with  the  generally  received  and 
as  yet  unquestioned  teaching  of  those  who  had 
studied  the  volumetric  relations  of  solid  species, 
that  this  law  was  conditioned  in  some  manner 
by  crystalline  form,  so  that  the  volume  of 
solids  (and  of  liquids,  also)  was  an  arbitrary 
and  a  variable  quantity,  instead  of  being,  as  in 
the  case  of  gases  and  vapors,  an  ideal  unit. 
The  general  principle  laid  down  by  Gmelin,  in 
his  Handbook  oi  Chemistry,  as  deduced  from 
the  studies  of  the  volumes  of  solids,  is  that 
"  isomorphous  substances  have  equal  atomic 
volumes."  ^  Otto,  also,  in  his  learned  review  of 
the  subject,  declares  that  Dumas,  whose  stud- 
ies, in  connection  with  Leroyer,  have  been  the 
point  of  departure  for  all  investigations  of  the 
1  Gmelin,  Cavendish  Society's  edition,  1848,  vol  i. 


r 


72 


A  Chemical  PJiilosophy. 


UEC;  ,  'I 


::lf|i 


! 


relation  between  the  specific  gravity  and  the 
chemical  composition  of  solids,  discovered  that 
the  relation  of  equal  volumes  "  is  connected 
with  the  crystalline  form,  as  it  exists  only  in 
isomorphous  species."  He  adds,  in  regard  to  the 
formula  p-T-d^=.v,  ''Dumas  was  the  first  to 
demonstrate  that  the  value  of  v  was  sensibly 
the  same  for  all  bodies  whose  isomorphous 
relations  had  been  established  by  Mitscher- 
lich."  1  Following  the  line  thus  indicated, 
chemists  have  been  led  to  compare  chiefly  such 
isomorphous  groups,  obtaining  results  which 
have  served  to  confirm  the  belief  in  the  correct- 
ness of  this  conclusion  as  to  the  significance 
of  crystalline  form. 

§  43.  All  this  was  before  me  in  1853,  when  I 
wrote,  with  regard  to  "  some  allied  and  isomor- 
phous species,"  that  "  H.  Kopp,  in  dividing  the 
assumed  equivalent  weights  of  such  bodies  by 
their  specific  gravities,  obtained  quantities  which 
were  found  to  be  equal  for  some  of  these  related 
species.  These  numbers  evidently  represent 
the  volumes  of  equivalents,  and,  in  accordance 


'  Otto,  Chemical  Reports  and  Memoirs  o£  the  Cavendish 
Society,  1848,  p.  67. 


The  Law  of  Volumes. 


73 


with  the  atomic  hypothesis,  are  said  to  denote 
the  atomic  volumes."  As  regards  the  pub- 
lished investigations  up  to  that  time,  it  was 
then  said:  "Their  results  show  that  the  vol- 
umes thus  calculated  for  related  species  of 
similar  crystalline  form  are  generally  identical, 
or  sustain  to  each  other  some  simple  ratio." 
From  the  comparisons  of  the  values  of  v  in  the 
alums  and  in  the  hydrated  sodium-orthophos- 
phates  and  ortharsenates,  and  from  other 
examples  which  were  apparently  in  accordance 
with  the  teachings  of  Dumas  as  to  the  identity 
of  volume  in  related  isomorphous  species,  the 
conclusion  was  then  reached  that  **  what  are 
called  the  atomic  volumes  of  crystallized  spe- 
cies are  the  comparative  volumes  of  their  crys- 
tals "  (4);  thus  stating  in  other  terms  the  con- 
clusion of  Dumas  that,  while  isomorphous 
substances  have  identical  volumes,  the  volumes 
in  different  crystalline  systems  were  unlike ;  a 
point  of  view  which  was  then  illustrated  at  some 
length.  In  1855,  I  had  more  than  one  confer- 
ence on  this  problem  with  Dumas,  who  had  read 
with  approval,  and  then  discussed  at  length, 
my  three  papers  of  1853  and   1854,  while  he 


«BI 


If 


74 


A  Chemical  Philosophy. 


ingeniously  explained  the  apparent  exceptions 
to  his  law  indicated  in  the  above  extracts,  by 
the  principle  of  polymerism. 

§  44.  That  some  broader  principle  than 
that  involved  in  isomorphism  underlies  these 
apparent  conformities  in  volume  was  soon 
after  perceived,  thoug-h  but  imperfectly  ap- 
prehended;  and  when,  in  1874,  the  essay  above 
quoted  was  republished  in  the  writer's  volume  of 
"Chemical  and  Geological  Essays,"  a  foot-note 
was  added  to  the  portion  from  which  was  taken 
the  above  cited  passage  as  to  the  relation  of 
volume  to  crystalline  form,  saying,  '*  The  con- 
clusions in  this  paragraph  may  be  liable  to  cor- 
rection ;  but  I  leave  them  as  they  were  printed 
twenty-one  years  since."  It  will  be  noted  that, 
in  reviewing  this  subject  in  1867,  it  was  said: 
"  The  variable  relation  to  space  of  the  empiri- 
cal equivalent  of  non-gaseous  species  or,  in 
other  words,  the  varying  equivalent  volume 
.  .  .  shows  that  there  exist  in  different  spe- 
cies very  unlike  degrees  of  condensation  "  (10) ; 
no  reference  being  made  to  crystalline  form  as 
in  any  way  conditioning  this  condensation. 
The  teaching  of  Dumas  and  his  successors  in 


The  Law  of  Volumes. 


;5 


this  field  of  inquiry  for  some  years,  however, 
maintained  the  writer,  in  common  with  other 
chemists,  in  the  belief  that  the  accident  of  crys- 
talline form  has  some  intimate  relation  with  con- 
densation. That  the  similar  values  of  v  in  the 
isomorphous  species  compared  involve  a  rela- 
tion of  equivalents  not  then  suspected,  is  made 
apparent  by  the  results  of  Graham's  studies  in 
liquid  diffusion,  then  made  known,  but  not  fully 
understood  even  by  himself ;  to  the  considera- 
tion of  which  we  shall  return  in  Chapter  XII. 

§  45.  When  we  have  once  attained  the  con- 
ception that  the  law  of  volumes  is  a  fundamen- 
tal and  a  universal  law,  to  which  all  species, 
whether  gaseous,  liquid,  or  solid,  whether  col- 
loid or  crystalline,  and  all  changes  of  state 
among  these,  are  subordinated,  the  solution  of 
the  great  problem  proposed  in  1853,  and  stated 
in  §  41,  is  seen  in  the  familiar  processes  of  the 
conversion  of  water  into  steam  and  of  steam 
into  water.  The  latter  is  the  change  of  the 
vapor  H2O  into  that  polymeric  liquid  species 
which,  at  its  maximum  density,  is  the  unit  of 
specific  gravity  for  all  liquids  and  solids.  Ac- 
cording to  the  calculation  in  Ganot's  Elements 


^^^^SSSISSSSiSBBs^^^S 


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76 


A  Chemical  Philosophy. 


de  Physique,^  based  on  a  comparison  of  the  den- 
sities of  steam  as  compared  with  air,  and  of  air 
as  compared  with  water,  the  ratio  between  the 
weights  of  equal  volumes  of  steam  at  100°  and 
760  mm.  pressure,  and  of  water  at  0°  is  i  :  1698. 
The  weights  of  equal  volumes  of  air  and  water, 
both  at  0°,  are  as  i  :  773  ;  but  those  of  air  at 
100°  and  water  at  0°  as  0.73178:773.  The 
density  of  steam  at  100°  and  760  mm.  as  com- 
pared with  air  under  the  same  conditions 
being  as  0.6225  :  i,  it  follows  that  the  ratio 
between  the  weights  of  equal  volumes  of  steam 
at  100°  and  water  at  o"  is  as  0.73178  X  0.6225  : 
773  =  0.4555:773=  1:1698. 

§  46.  But  we  may  approach  this  question 
more  directly,  by  calculating  the  specific  gravity 
of  steam  from  that  of  hydrogen.  Regnault 
found  for  the  weight  of  one  litre  of  hydrogen  in 
the  latitude  of  Paris  at  0°  and  760  mm.  pressure, 
0.089578  gramme,  which  from  its  expansion  as 
determined  by  him  would  at  100°  be  0.065572 
gramme.  If  we  assume  the  equivalent  of  oxy- 
gen as  16.0,  we  have  for  the  weight  of  a  litre 
of  steam,  H2O,  at    100°  and  760  mm.,  0.590148 

1  Ganot,  Atkinson's  translation,  fifth  edition,  1872,  p.  290. 


The  Latv  of  Volumes. 


77 


gramme,  and,  dividing  by  this  number  the 
weight  of  one  litre  of  water  at  4°=iooo.o 
grammes,  we  get  1694.49.  If,  however,  we  take 
for  oxygen  the  number  15.9633  (the  best  figure 
obtainable),  we  have  for  the  weight  of  a  litre  of 
steam  at  100°  and  760  mm.,  0.58894  gramme, 
and,  taking  this  number  as  the  divisor,  obtain 
1697.96;  but,  as  water  at  0°  has  a  specific 
gravity  of  0.99987  (Rosetti),  the  ratio  between 
steam  at  1000  and  760  mm.  and  water  at  0° 
becomes  i  :  1697.74. 

The  close  approximation  to  the  directly  calcu- 
lated ratio  I  :  1698  got  by  employing  the  cor- 
rected equivalent  weight  of  oxygen  is  such  that 
we  may  assume  this  figure  as  representing  the 
true  ratio.  But,  in  order  to  establish  the  amount 
of  condensation  in  the  conversion  of  steam  into 
water,  we  must  take  the  specific  gravity  of  this 
liquid  at  the  temperature  of  condensation,  100°; 
and  this,  according  to  the  determination  of 
Kopp,  is  0.95878. 

1. 00000  :  0.95878  :  :  1698  :,r  =  1628.04. 

This  figure  represents  the  number  of  volumes 
of  steam  at  100°  and  760  mm.  which  are  con- 
densed  in  one  volume  of  water  at   the  same 


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78 


A  Chemical  Philosophy. 


temperature.  The  equivalent  weight  of  H^O 
being,  according  to  our  second  calculation,  not 
18.0,  but,  more  exactly,  17.9633^  that  of  water, 
which  is  i628(H20)  =  29,244.^  In  first  announc- 
ing these  conclusions,  in  September,  1886  (17), 
by  making  HoO  =:  18,  the  number  29,304  was 
arrived  at  for  the  equivalent  weight  of  water ; 
and  the  same  figure  is  given  in  the  author's 
Mineral  Physiology  and  Physiography,  p.  xvii. 
Ice  is,  perhaps,  I494(H20),  which  corresponds 
to  a  specific  gravity  of  0.9177. 

If  we  take,  as  a  close  approximation,  for  the 
weight  of  a  litre  of  hydrogen  at  760  mm.  and  0°, 
tne  ordinarily  received  number,  0.0896  gramme, 
we  find  for  the  same  at  100°,  0.065588  gramme, 
and  for  water-vapor  under  these  conditions, 
0.589088  gramme.  The  weight  of  the  litre 
of  water  at  100°  being  95878  grammes,  we 
have : — 

0.065588  : 958.78  ::  I  :t=  14,618.2. 

Multiplying  by  two  the  value  of  x,  which  rep- 


*  This  corrected  value  for  the  equivalent  weight  of  water  is 
given  in  Science  for  November  ig,  in  an  abstract  of  the  author's 
coninuniication  on  "  A  I^asis  for  Chemistry  "  to  the  National 
Academy  of  Sciences,  November  9,  1SS6. 


The  Lazv  of  Volumes. 


79 


resents  the  relation  of  weight  between  equal 
volumes  of  H2  and  water,  both  at  100°,  we  have 
29,236.4,  or  very  nearly  that  corresponding  to 
i628(H20)  =  29,244. 

In  1885,  when  the  problem  of  fixing  the 
equivalent  weights  of  liquid  and  solid  species 
had  not  yet  been  solved,  it  was  shown  that  this 
weight  for  certain  solid  species,  such  as  the 
salts  of  the  cobaltic  ammonias,  and  the  poly- 
tungstates,  must  be  several  thousand  times  that 
of  hydrogen  (§  26),  with  correspondingly  large 
equivalent  volumes.  Having  then  noticed  what, 
in  the  language  of  the  atomic  theory,  were  called 
the  unit-weight  and  the  unit-volume  (§  48),  rep- 
resented by  P  and  V  (=/  and  7'),  it  was  said : 
"The  relations  alike  of  this  unit-weight  and 
unit-volume  to  those  of  the  molecule  to 
which  it  belongs  are  unknown.  But  this  mole- 
cule has,  by  our  hypothesis,  a  constant  volume, 
for  which  an  expression  is  yet  wanting,  and  can, 
so  far  as  known,  only  be  attained  by  assuming 
as  unity  the  number  which  corresponds  to  the 
highest  discovered  value  of  V.  The  true  unit 
of  molecular  volume  will  probably  still  be  some 
multinle  of  this  number."    (1.6.) 


Hi 


CHAPTER   X. 

METAMORPHOSIS    IN    CHEMISTRY. 

§  47.  Chemism  may  be  comprehensively  de- 
fined as  the  production  of  new  chemical  species, 
either  by  integration  or  by  disintegration ; 
and  these  changes,  as  has  been  farther  shown, 
may  be  either  homogeneous  or  heterogeneous. 
In  heterogeneous  integration  two  species  of 
unlike  centesimal  composition  unite ;  and  in 
heterogeneous  differentiation  a  species  is  re- 
solved into  two  or  more  unlike  ones.  This 
genesis  of  complex  species  having  a  centesimal 
composition  unlike  the  parents,  we  have  desig- 
nated aa  metagenesis,  as  set  forth  at  some 
length  in  Chapter  II.  In  homogeneous  chemi- 
cal change  we  have  the  production  of  new 
species  by  the  union  or  integration  of  two  or 
more  like  species,  either  elemental,  or,  if  com- 
plex, of  identical  centesimal  composition ;  or 
conversely,   the    disintegration   of    such    com- 

80 


Metamorphosis  in  Chemistry. 


8i 


pounded  species  into  simpler  and  lilce  forms. 
These  homogeneous  chemical  changes  consti- 
tute what  we  have  distinguished  as  metamorpho- 
sis in  chemistry,  and  include  both  polymeriza- 
tion and  depolymerization.  They  have  long 
been  familiar  to  chemists,  alike  in  so-called  ele- 
ments and  in  many  hydrocarbonaceous  bodies, 
as  has  been  noticed  in  §  5,  but  their  importance 
is  such  as  to  demand  a  special  discussion. 

§  48.  It  has  already  been  shown  that  the 
bodies  derived  from  gases  and  vapors  by  lique- 
faction and  sohdification  are  distinct  species, 
and  are  polymers  of  these;  their  generation 
being  by  a  process  of  homogeneous  integra- 
tion, or,  in  other  words,  of  metamorphosis 
by  condensation  ;  while  the  vaporization  of 
such  liquids  and  solids  is  homogeneous  disin- 
tegration, or  metamorphosis  by  expansion. 
For  all  species  which  are  said  to  volatilize 
without  decomposition,  —  that  is  to  say,  which 
may  be  converted  into  vapor  without  hetero- 
geneous differentiation ;  or  which,  in  other 
words,  yield  thereby  simpler  species  having 
the  same  centesimal  composition  as  their  par- 
ent, —  the  equivalent  weights  are  known  from 


82 


A  Chemical  Philosophy. 


their  vapor-densitics ;  and  the  coefficient  of  con- 
densation for  such  liquid  and  solid  species  is 
directly  found  by  comparing  the  density  of 
these  gaseous  species  with  that  of  their  liquid 
and  solid  polymers,  as  already  shown  in  the 
case  of  steam,  water,  and  ice. 

When,  however,  we  have  to  deal  with  species 
which  are  too  fixed  in  the  fire  to  admit  of  vapor- 
determinations,  or  with  those  which  by  heat 
undergo  heterogeneous  disintegration,  —  as,  for 
example,  sugars,  carbon-spars,  and  hydrous  sil- 
icates, —  in  place  of  the  unit-weight  deduced 
from  vapor-density  (as  in  the  case  of  water, 
mercuric  chlorid,  or  sulphur),  we  may  make  the 
simplest  formula  deduced  from  analysis  serve 
as  the  unit ;  or,  for  greater  convenience  in  calcu- 
lation, may,  in  the  case  of  oxyds  and  silicates, 
assign  to  it  a  value  corresponding  to  H  =  i  and 
0  =  8.  The  unit  for  silica  thus  becomes  SiOg 
=  60-7-4=15;  that  for  alumina  Al,06=i02 
-1-6=:  17  ;  and  that  for  the  magnesian  silicate 
forsterite,SiMg204  =  140-^8=  17.5.  Such  unit- 
weights  have  been  employed  by  the  writer  in 
his  late  essay  on  A  Natural  System  in  Miner- 
alogy (16),  in  the  tables  of  which  they  have 


Metamorphosis  in  C/iemistry. 


83 


been  represented  by  P ;  while  the  values  got  by 
dividing  these  numbers  by  the  specific  gravi- 
ties have  been  called  unit-volumes,  and  desig- 
nated by  V.  That  the  units  which  make  up 
the  polymers  in  such  non-volatile  species  are, 
however,  far  greater  than  these  unit-weights 
is  apparent  when  we  consider  the  highly  com- 
plex formulas,  and  the  elevated  equivalent 
weights,  to  which  we  are  led  by  the  analyses 
of  many  species,  as  already  noted  in  Chapter  VI. 
§  49.  To  similar  conclusions  are  we  conducted 
by  the  study  of  the  phenomena  of  metamorpho- 
sis in  certain  hydrocarbonaceous  species,  nota- 
ble examples  of  which  are  seen  in  the  alde- 
hydes, and  in  the  turpentine-oils.  It  will  be 
remembered  that  normal  acetic  aldehyde,  with 
a  vapor-density  corresponding  to  C2H4O  and  a 
specific  gravity  of  about  .800,  boiling  at  21°,  is, 
in  presence  of  small  quantities  of  various  re- 
agents, such  as  chlorhydric  acid  or  sulphurous 
anhydrid,  at  ordinary  temperatures,  rapidly  con- 
verted, with  considcrabh  evolution  of  heat,  into 
paraldehyde,  a  liquid  of  specific  gravity  .998, 
boiling  at  124°,  becoming  a  crystalline  solid  at 
10*,  and,  from  its  vapor-density,  a  tri-aldehyde 


84 


A  Chemical  Philosophy. 


3(C2H40).  The  same  reagents,  at  low  tempera- 
tures, convert  aldehyde  into  another  modifica- 
tion, metaldehyde,  which  is  a  crystalline  solid 
at  100°,  and  at  a  higher  temperature  volatilizes 
without  fusion.  From  the  readiness  with 
which  (like  paraldehyde)  it  is,  at  a  higher  tem- 
perature, reconverted  into  normal  aldehyde,  the 
vapor-density  of  this  polyaldehyde  ;ir(C2H40) 
cannot  be  determined. 

Chloral,  CjCHCyO,  in  like  manner,  readily 
changes  into  a  white  insoluble  species,  meta- 
chloral,  of  unknown  equivalent  weight,  which 
at  180°  is  converted  into  the  vapor  of  normal 
chloral,  volatile  at  95°.  Still  more  remarkable 
is  the  case  of  formic  aldehyde,  or  methylene 
oxyd,  at  ordinary  temperatures  a  gas  soluble  in 
water,  and,  as  shown  by  its  vapor-density, 
CH20  =  30,  which  spontaneously  changes  into  a 
white,  insoluble  polymer.  This,  which  is  volatile 
at  100°,  melts  at  152°,  and  its  vapor,  which  is 
perhaps  3(CH20),  is  at  a  higher  temperature 
metamorphosed  into  the  normal  aldehyde,  which 
polymerizes  again  on  cooling.  We  have  thus 
an  example  of  two  interconvertible  species  of 
identical  centesimal  composition,  the  one  a  gas, 


Metamorphosis  in  Chemistry. 


85 


soluble  in  water,  and  the  other  a  white  insoluble 
solid. 

§  50.  Chemists  have  long  distinguished 
among  the  turpentine-oils  a  considerable  num- 
ber of  species  which,  while  having  the  same 
centesimal  composition,  differ  considerably  not 
only  in  chemical  relations,  in  optical  characters, 
and  in, being  liquid  or  solid  at  ordinary  temper- 
atures, but  in  specific  gravity  and  in  boiling- 
point.  Some  of  these  are  found  in  nature, 
while  others  are  produced  by  the  transforma- 
tions of  ordinary  French  or  American  turpen- 
tine-oil. This,  to  which  the  formula  CiqHis  is 
assigned,  is  readily  metamorphosed  by  heat, 
and  by  many  reagents,  giving  rise  to  a  large 
number  of  new  species.  Some  of  these  belong 
(together  with  various  natural  oils)  to  the  class 
of  proper  turpenes,  including  several  groups,  to 
all  of  which  is  assigned  the  above  formula. 
Among  these  natural  and  artificial  turpenes 
are  the  liquid  pinenes,  boiling  at  about  160°  ; 
the  camphenes,  having  a  similar  boiling-point, 
but  forming  crystalline  solids  below  50° ;  and 
the  limonenes,  liquids  boiling  about  175°- 177% 
—  with  several  other  groups  —  each   of  these 


It 


111' 


.  I 


.6 


A  Chemical  Philosophy. 


i 


including  varieties  or  sub-species,  differing  in 
optical  characters  and  in  chemical  relations. 
Besides  these  true  turpenes  arc  others,  re- 
garded as  sesquiturpenes  (C15H24),  boiling  at 
250°-26o° ;  diturpene,  or  colophene  (C20H32), 
boiling  at  300°;  and  poly  turpenes,  of  still 
higher  equivalent  and  unknown  complexity, 
boiling  above  360°. 

§  51.  When  the  vapor  of  turpentine-oil  is 
passed  through  a  tube  heated  to  low  redness, 
the  products  of  condensation  yield,  besides 
different  turpenes,  and  colophene,  a  considera- 
ble portion  of  a  very  volatile  liquid,  boiling 
between  37°  and  40°,  with  a  vapor-density 
showing  it  to  be  a  hemiturpene  (QH^),  which 
is  designated  pentine,  and  is  apparently  identi- 
cal with  what  have  been  called  isoprene  and 
valerylene.  Besides  these  homogeneous  trans- 
formations or  metamorphoses,  both  of  integra- 
tion and  differentiation,  produced  by  heat  in 
turpentine-oil,  there  is  a  simultaneous  hetero- 
geneous differentiation  of  a  portion,  resulting 
in  the  production  of  a  homologue  of  pentine, 
namely,  heptine  (C-H12),  and  probably,  also,  of 
the  intermediate  hexine,  together  with   hydro- 


Metamorphosis  in  Chemistry. 


^7 


carbons  of  the  benzene-toluene  scries,  and  some 
permanent  gases. 

When  pontine  is  heated  in  scaled  tubes  to 
280°,  it  undergoes  a  partial  polymerization,  a 
portion  of  it  being  changed  into  a  turpene,  with 
a  little  colophene.  When  distilled  in  open 
vessels,  the  transformation  of  this  volatile 
liquid  into  less  volatile  products  causes  the  tem- 
perature of  the  mass  to  rise  rapidly,  without 
the  aid  of  heat  from  without,  the  action  some- 
times becoming  explosive.  A  similar  rise  of 
temperature  is  noticed  in  the  rapid  polymeriza- 
tion of  aldehyde,  and  in  that  of  ordinary  turpen- 
tine-oil, which  is  produced  by  contact  with 
sulphuric  acid  or  with  small  portions  of  fluorid 
of  boron. ^  Wallach,  who  has  lately  reviewed 
the  history  of  the  various  turpentine-oils,  and 
the  products  of  the  polymerization  of  pontine 
and  turpene,  has  designated  these  as  pentine 
(CjHs) ;  di-pentine,  including  the  various  tur- 
pcnes     (CjoHjo)  ;      tri-pentine,     including     also 


1  See  Watts,  Dictionary  of  Chemistr}',  under  Turpentine- 
Oil;  also  the  papers  of  Armstrong  and  Tilden,  Journal  of 
the  Chemical  Society  of  London,  vols.  35  and  45 ;  and  later, 
Wallach,  Liehigs  Annalen,  vol.  ccx.xvii.,  p.  277. 


s 

'3 

Ilitti 


1 

■ 

- 

J 

88 


A  CJicmical  Philosophy. 


various  sub-species  (Cu  24)  >  ^'^^  tetra-pentine, 
or  colophcnc  (C20I  1^2)  \  —  besides  the  higher 
polymers,  of  unknown  complexity,  including 
the  so-called  mctaturpene.  The  specific  grav- 
ity of  pontine  (mono-pentine)  is  about  .680 ; 
that  of  the  turpenes  varies,  but  is  not  far  from 
.850;  and  that  of  the  higher  polymers  is  from 
.920  to  above  i.oo. 

§  52.  The  disengagement  of  heat,  noticed  in 
the  polymerization  of  aldehyde,  of  pontine,  and 
of  turpentine-oil,  is  analogous  to  that,  resulting 
in  vivid  incandescence  from  internal  change, 
which  takes  place  when  many  amorphous 
bodies  are  heated  to  low  redness,  by  which 
change,  in  the  language  of  Gmclin,  they  ac- 
quire "  greater  specific  gravity,  greater  hard- 
ness, and  less  solubility."  This  incandescence 
is  observed  in  titanic,  tantalic,  molybdous,  zir- 
conic,  chromic,  and  ferric  oxyds,  in  magnesium 
pyrophosphate,  and  in  certain  artificial  arse- 
nates and  antimonates,  as  well  as  in  native 
minerals,  like  euxenite,  gadolinite,  and  allanite. 
Such  as  these  were  called  by  Scheerer  pyro- 
gnomic  species,  and  adduced  by  him  as  evidence 
that  the  granitic  veinstones  in  which  they  are 


Metamorphosis  in  C lie  mis  try. 


89 


found  were  not  formed  at  very  elevated  tem- 
peratures.' 

§  53.  We  have  already  noticed  the  question 
of  metamorphosis  among  so-called  elemental 
species,  as  discussed  in  1S48  (§  5).  As  re- 
gards sulphur,  and  the  threefold  condensation 
of  its  vapor  then  suggested,  it  will  be  remem- 
bered that,  as  was  shown  by  Bineau,  in  1869, 
this  vapor,  at  temperatures  approaching  1000°, 
is  expanded  to  that  of  normal  sulphur.  To 
this  we  have  a  parallel  in  the  cases  of  paralde- 
hyde and  metaldehyde,  readily  converted  into 
aldehyde,  and  in  turpentine-oil,  itself  a  poly- 
mer, which  may  be  volatilized  as  such,  but  at 
an  elevated  temperature  is  resolved  into  pentine 
(CsHg),  which,  as  we  have  seen,  readily  passes 
again  into  CioHig,  and  still  higher  polymers. 

The  effect  of  a  given  temperature  upon  a 
vapor  cannot  be  determined  ^  priori ;  while 
sulphur  and  turpentine-oil  volatilize  as  poly- 
mers, the  vapors  of  which  undergo  homogene- 
ous differentiation  only  at  much  higher  temper- 

^  See,  in  this  connection,  Gmelin's  Hnndbook,  Cavendish 
Society's  Edition,  I.  106,  107 ;  also  the  author's  Mineral  Phys- 
iology, etc.,  p.  96. 


90 


A  Chemical  Philosophy. 


atures,  the  vapor  of  water  assumes  at  once 
its  normal  type,  H20>  and  at  higher  temper- 
atures undergoes  heterogeneous  differentiation, 
or  metagenesis,  being  resolved  into  hydrogen 
and  oxygen.  There  are,  doubtless,  other  gas- 
eous polymers,  which,  like  tri-sulphur,  S3,  and 
di-pentine,  2(C5H8),  exist  within  certain  limits  of 
temperature  and  pressure.  In  this  connection, 
the  studies  of  Cagniard  de  la  Tour,  of  Drion, 
and  of  Andrews,  on  the  conversion  of  liquids 
into  gases,  are  very  important,  and  help  to 
enlarge  our  conceptions  of  this  polymerism  in 
vapors  under  great  pressure ;  while  farther 
homogeneous  integration,  at  lower  tempera- 
tures, gives  rise  to  liquid  and  solid  species, 
more  or  less  stable  at  the  ordinary  atmos- 
pheric pressure. 

§  54.  The  same  gaseous  species  may  yield 
two  or  more  liquid  or  solid  species  of  different 
degrees  of  density,  and  of  different  stability  as 
well,  as  is  evinced  by  differences  in  boiling- 
point.  This  is  seen  from  the  comparison  of 
the  various  groups  of  liquid  and  solid  turpcnes, 
or  di-pentines,  all  of  which  are  distinct  from 
the  liquid  forms  alike  of  true   pentine  (mono- 


Metmnorphosis  in  Chemistry. 


91 


pentiiie),  of  tri-pentine,  and  of  tctra-pentine, 
and  constitute  different  liquid  polymers  of 
2(C5H8).  Analogous  differences  are  observed 
in  the  isomeric  butylic  alcohols,  which,  with 
a  common  vapor-density,  exhibit,  like  the  tur- 
penes,  considerable  differences  alike  in  specific 
gravity  and  in  boiling-point,  and  correspond  to 
greater  or  less  degrees  of  condensation.  The 
various  di-pentines  are  to  be  compared  to  ice 
and  water.  The  latter,  under  favorable  condi- 
tions, is  a  liquid  of  density  i.ooo  (nearly),  even 
at  — 10°,  though  then  readily  transformed  into 
ice,  with  a  density  of  0.917.  In  like  manner, 
we  have,  at  ordinary  temperatures,  besides  the 
unstable  liquid  phosphorus  of  density  1.77,  the 
ordinary  and  readily  fusible  species  with  a 
density  of  1.82,  and  the  red  crystalline  species 
of  density  2.35,  all  of  which,  so  far  as  known, 
are  directly  changed  by  heat  into  the  same 
elemental  or  normal  vapor,  without  gaseous 
polymerism,  precisely  as  both  ice  and  water 
pass  directly  into  the  normal  vapor,  H^^O. 

§  55.  A  remarkable  example  of  metamorpho- 
sis in  an  elemental  species  is  afforded  by  tin, 
which,  iis   observed   by  Fritzsche,  Oudemans, 


!*i  '■>. 


u 


92 


A  Chemical  Philosophy. 


Schertel,  and  Richards,^  when  exposed  to  great 
natural  cold,  is  changed  from  the  white,  tough, 
malleable  metal,  having  a  specific  gravity  of 
about  7.30,  to  a  gray,  brittle,  crystalline  body, 
of  much  less  density.  This  change  takes  place 
not  only  in  pure  block  tin  but,  as  observed  by 
Richards,  in  ingots  containing  2.5  per  cent  of 
mercury,  the  change,  at  a  minimum  tempera- 
ture of  about  —  180,  gradually  extending,  in 
this  case,  from  certain  centres,  so  as  in  a  few 
weeks  to  involve  the  whole  mass;  which  had  a 
radiated  structure,  and  was  compared  in  aspect 
to  stibnite.  Its  density  was  found  by  Richards 
to  be  6.175,  that  of  the  unchanged  portions 
being  7.387.  Other  observers  have  found  for 
this  altered  form,  with  pure  tin,  densities  of  6.0 
and  even  of  5.8.  Its  instability  makes  this 
determinatioi:  difficult,  since  the  gray,  brittle 
species  is  readily  changed  into  white  tin  by 
strong  pressure,  by  a  sudden  blow,  or  by  im- 
mersion in  hot  water,  which  restores  to  it  its 
toughness  and  its  original  density  of  7.30.    The 


1  Watts's  Dictionary  of  Chemistry,  Third  Supplement; 
also  Richards,  in  Transactions  American  Institute  of  Mining 
Engineers,  xi.  221. 


Metamorphosis  in  Chemistry. 


93 


gray  tin  exhibits,  alike  in  acid  and  in  alkaline 
liquids,  electrical  relations  different  from  those 
of  the  ordinary  metal.  . 

This  metamorphosis  of  tin  is  comparable 
to  that  of  water  into  ice  by  cold,  or  that  of 
aragonite  into  calcite  by  heat,  the  transforma- 
tion in  each  case  being  one  of  homogeneous 
disintegration  from  a  denser  to  a  lighter  species. 
It  is  not  improbable  that  similar  changes  of  state 
analogous  to  this  may  take  place  in  other  bodies, 
and  that  the  temporary  production  of  a  simi- 
larly brittle  and  chemically  unstable  form  of 
iron,  under  like  circumstances,  may  explain  the 
apparently  ready  frangibility  of  that  metal 
when  exposed  to  severe  frosts. 

§  56.  Tn  1848  (§  5),  in  calling  attention  to 
the  fact  that  sulphur-vapor  in  the  only  form 
then  known  was  tri-sulphur,  SSS,  which  was 
compared  to  SOO,  it  was  suggested  that  ozone 
might  be  tri-oxygen,  OOO.  It  however  is  now 
known  that,  though  condensed  oxygen,  its 
equivalent  weight  corresponds  to  one-half  of 
this,  or  to  000  doubled  in  volume  by  homo- 
geneous disintegration.  Making  H^  the  unit 
of  volume,  we  have  for  the  vapor  of  tri-sulphur 


I!     ^N 


Is 


m 


94 


A  Chemical  Philosophy, 


Sg,  and  for  sulphur-vapor  above  500°  Sj.  If, 
then,  normal  oxygen  is  O2,  ozone  is  not  Oe, 
but  O3.  So,  the  vapor  of  iodine,  I2  at  tem- 
peratures approaching  1500°,  is,  as  shown  by 
Crafts,  changed  in  great  part  into  a  species,  Ij, 
having  but  one-half  the  density  which  belongs 
to  normal  iodine-vapor.  i\  similar  change,  to  a 
less  extent,  is  wrought  at  high  temperatures  in 
bromine  and  chlorine,  as  shown  by  Victor 
Meyer  and  others.  These  so-called  elemental 
gaseous  species  thus  undergo  at  higher  tempera- 
tures a  homogeneous  disintegration,  like  that  of 
the  vapor  of  di-pentine,  when,  by  heat,  it  is 
changed   into  pentine. 

§  57.  All  of  these,  and  similar  changes,  are 
but  examples  of  that  law  of  dissociation  by 
heat,  which  includes  alike  so-called  elements 
and  compounds ;  and,  as  the  writer  was  the 
first  to  teach,  in  1S67,  is  universal,  and  applies 
to  the  chemistry  of  stellar  matter.  While 
oxygen,  nitrogen,  and  hydrogen  give  no  evi- 
dence of  similar  dissociation  in  our  laboratories, 
it  was  then  suggested  that  they  may  suffer  it 
in  the  solar  fires  ;  and  later,  in  1874,  it  was 
pointed  out  that  the  unknown  element,  appar- 


Metamorphosis  in  Chemistry. 


95 


ently  of  great  tenuity,  shown  by  the  spectro- 
scope in  the  solar  chromosphere,  as  line  1474, 
Kirchhoff,  is  probably  a  more  elemental  form  of 
matter  than  any  known  on  earth,  if  not  the 
primal  element  from  which  all  others  have  been 
generated,  as  set  forth  at  length  in  Chapter  Til. 
It  is  not  improbable  that  the  power  of  flame  or 
the  electric  spark  to  effect  the  sudden  union  of 
chlorine  and  of  oxygen  with  hydrogen  may  be 
due  to  the  effect  of  intense  heat  in  separating 
momentarily  into  simpler  form  portions  of 
these  gases,  so  that  we  may  have  in  the  process 
of  their  combination  a  union  of  unknown  ele- 
mental and  less  dense  species. 

§  58.  Whether  in  any  case  the  homogeneous 
differentiation  or  depolymerization  of  a  volatile 
condensed  species  will  be  effected  at  a  single 
step  as,  under  the  ordinary  pressure  at  least, 
is  the  case  with  water,  the  alcohols,  and  most 
other  liquids ;  or  whether,  as  with  sulphur  or 
iodine,  or  with  the  gaseous  polymers  of  pen- 
tine  and  aldehyde,  by  two  or  more  successive 
steps,  cannot,  in  the  present  state  of  our 
knowledge,  be  foreseen.  When,  therefore,  we 
have  to  do  with  species  which  are  not  suscepti- 


'^11 


M 


I 


Ml' 


^fiii 


ill 


m 


96 


A  Chemical  Philosophy. 


ble  of  metamorphosis  by  expansion,  —  that  is 
to  say,  of  integral  volatilization,  —  we  cannot, 
in  studying  their  condensation,  know  whether 
we  have  to  deal  with  the  simplest  possible 
formula,  or  with  some  multiple  thereof.  Did 
we  not  know  the  existence  alike  of  mono- 
pentine,  and  of  its  polymers,  di-pentine,  tri- 
pentine,  and  tetra-pentine,  we  could  not  tell 
how  to  write  the  formula  of  solid  camphene,  or 
of  liquid  isoprene,  pinene,  limonene,  or  colo- 
phene,  although  the  equivalent  weights  of 
these  had  already  been  fixed  from  their  spe- 
cific gravities.  In  other  words,  we  could  not 
determine  whether  the  unit  by  the  polymeriza- 
tion of  which  these  liquid  and  solid  species 
have  been  generated  is,  in  any  given  case,  QHg, 
C10H16,  C15H04,  or  C20H32.  In  like  manner,  we 
might  ask  whether  the  unit  in  crystalline 
sulphur  is  mono-sulphur,  8=32,  or  tri-sulphur, 
83  =  96.  Yet  the  determination  of  these  num- 
bers, in  the  one  case  and  in  the  other,  is  neces- 
sary in  order  to  fix  the  coefficient  of  condensa- 
tion in  liquid  and  solid  species. 

§  59.  Resuming  here  what  has  been  said  of 
metamorphosis,  and  its   relations  to  metagen- 


■t  i  1 


Metamorphosis  in  Chemistry. 


97 


esis,  we  repeat,  that  the  systems  of  structural 
formulas,  and  of  types  in  chemistry,  are  but 
expressions  of  the  genealogical  relations  of 
species,  as  deduced  from  a  consideration  of 
the  phenomena  of  metagenesis.  This  precedes 
metamorphosis,  which,  by  homogeneous  inte- 
gration, converts  the  simpler  or  normal  species 
into  polymeric  species  of  higher  equivalent 
weights.  In  these  condensed  species,  as  al- 
ready pointed  out,  there  is  observed  an  increase, 
corresponding  to  the  degree  of  condensation, 
in  their  power  of  resistance  to  chemical  change  ; 
as  shown  in  diminished  volatility,  fusibility,  and 
solubility,  not  less  than  in  increased  hardness. 
Carbon  dioxyd,  CO2,  is  a  gas,  and  only  under 
exceptional  conditions  gives  rise  to  liquid  and 
solid  polymers,  which  are  rapidly  depolymerized 
at  the  ordinary  pressure  and  temperature ; 
while  the  corresponding  silicon  dioxyd,  Si02,  is 
scarcely  known  except  in  insoluble  crystalline 
or  colloidal  polymeric  forms,  although  it  is  prob- 
able that,  at  a  very  high  temperature,  it  assumes 
the  gaseous  form  of  normal  silicon  dioxyd.^ 

'  In  an  experiment  made  by  the  writer  in  September,  1885, 
with  the  electrical  furnace  of  the  Messrs.  Cowles,  in  which  the 


i  1^ 


A  Chemical  Philosophy. 

§  60.  Many  complex  species,  when  generated 
by  double  decomposition  in  aqueous  solutions, 
remain  dissolved  for  a  greater  or  less  time 
before  separating  in  an  insoluble  condition. 
The  interval  which  thus  elapses  before  the  for- 
mation of  such  precipitates,  as  in  the  case  of 
ammonio-magnesium  phosphate,  of  strontium 
sulphate,  and  of  gypsum,  among  others,  is  that 
required  to  convert  the  soluble  normal  species, 
by  homogeneous  integration,  into  insoluble 
polymeric   species. 

Theoretically,  all  species  may  exist  in  their 
normal  or  soluble  forms ;  and  it  is  this  condi- 
tion which  constitutes  the  nascent  state  of 
bodies.  The  manner  in  which  oxyds  like  those 
of  silicon,  aluminium,  and  iron  are  not  only 
found  in  nature,  but  are  separated  in  our  labor- 
atories in  a  crystalline  state  from  aqueous  solu- 

current  of  a  dynamo-electric  machine,  of  thirty  horse-power, 
was  passed  through  a  horizontal  column  of  fragments  of  char- 
coal, mingled  with  pure  silicious  sand,  while  a  portion  of  this 
was  reduced  to  silicon,  and  a  still  larger  amount  fused  into  a 
glass,  a  small  portion  was  found  in  botryoidal  masses,  like 
chalcedony  in  aspect,  adhering  to  the  covering  tiles  of  the  fur- 
nace, apparently  fr^m  direct  volatilization.  See  Transactions 
American  Institute  of  Mining  Engineers  for  1885;  and  Chemi- 
cal Ne  .vs  for  Nov.  C,  1885 ;  pp.  235-236. 


Metamorphosis  in  Chemistry. 


m 


tions,  shows  that  these  oxyds,  before  passing 
into  insoluble  and  highly  condensed  polymeric 
forms,  have,  like  the  compounds  named  above, 
enjoyed  a  temporary  solubility  in  water.  The 
very  soluble  forms  of  silicic,  titanic,  stannic, 
tungstic,  ferric,  chromic,  and  aluminic  oxyds, 
which  were  especially  studied  by  Graham,  are 
well  known  examples  of  this.  That  the  mineral 
silicates,  sulphids,  etc.,  found  in  veinstones 
have  also  at  one  time  been  in  similar  condi- 
tions, is  evident  from  geognostical  observations.* 
This  question  was  discussed  by  the  present 
writer  in  1872,  when  it  was  said  that  "it  will 
probably  one  day  be  shown  that  for  the  greater 
number  of  those  oxygenized  compounds  which 
we  call  insoluble,  there  exists  a  modification 
soluble  in  water."  The  tendency  of  most 
normal  species  to  pass  into  polymeric  or  con- 
densed forms,  of  greater  or  less  stability,  is  a 
fact  of  fundamental  importance  in  chemistry. 

1  Chemical  and  Geological  Essays,  page  223,  note. 


[ii 


.•f< 


I 


if- 
II  • 


CHAPTER   XI. 

THE   LAW   OF   DENSITIES. 

§  6 1.  The  significance  of  the  question  raised 
in  §  58  of  the  last  chapter  will  be  made 
more  apparent  in  considering  the  densities  of 
some  well  known  solid  species ;  as,  for  exam- 
ple, the  minerals  included  under  the  name  of 
calcareous  spar  or  calcite,  and  consisting  of 
calcium-carbonate.  In  calculating,  in  Chapter 
IX.,  the  equivalent  weight  of  water,  it  has 
been  shown  that  the  direct  determination  of 
the  ratio  between  the  volume  of  water  at  0° 
and  that  of  steam  at  100°  (=  i  :  1698)  agrees 
closely  with  the  number  calculated  from  the 
density  of  hydrogen  gas  (H  =  i.o),  if  that  of 
oxygen  be  taken  at  15.9633  instead  of  16.0,  as 
formerly  admitted.  This  correction  makes,  for 
water,  into  which  the  oxygen-value  enters  so 
largely,  a  noteworthy  difference,  and  gives 
29,244   instead   of   29,304,    as    the    equivalent 

100 


The  Law  of  Densities. 


lOI 


weight  of  water,  i628(H20)-  ^^'^  species  in 
which  this  value  enters  in  smaller  proportion, 
the  difference  is  of  less  moment.  Thus,  for 
calcium-carbonate,  CCaOg,  which,  with  0=  i6, 
has  a  combining  number  of  loo.o,  we  find,  on 
substituting  the  corrected  value,  0=15.9633, 
that  the  number  is  99.89. 

§  62.  Dividing  the  first  combining  number  by 
2.735,  ^s  the  approximate  density  of  calcite 
(water=  i. 000),  we  get  100.0-7- 2.735  =  35.56  as 
the  reciprocal  of  the  coefficient  of  condensation, 
which  gives  800  as  the  coefficient  itself ;  since 
800X35.56  =  29,248,  or  almost  exactly  the 
equivalent  weight  of  water,  and  consequently 
for  the  equivalent  weight  of  calcite  itself  the 
number  80,000.  Substituting  the  second  com- 
bining number,  99.89,  we  obtain  instead,  79,922. 
But,  since  the  specific  gravity  is  directly  as  the 
equivalent  weight,  we  have  for  these  two  val- 
ues respectively,  as  follows  :  — 

29,244:80,000: :  I  :;ir^  2.7325. 
29,244  :  79,922  ::  I  :.r  =  2.7356. 


The  small  difference  of  about  .003  in  these 
two    calculations    of    the    specific    gravity    of 


102 


A  Chemical  Philosophy. 


I 


i'i.i 


1^' 


calcite,  which  includes  nearly  one-half  its 
weight  of  oxygen,  being  within  the  limits 
of  error  in  the  ordinary  determinations  of  den- 
sity in  solid  species,  may  be  disregarded,  and 
in  studying  the  density  of  the  various  native 
oxyds  and  silicates,  the  equivalent  weights 
as  generally  calculated,  with  0=i6,  may  be 
employed. 

§  63.  Now,  while  the  density  of  any  given 
gas  or  vapor  is  constant  at  a  given  temperature 
and  pressure,  that  of  many  liquids  and  solids 
of  identical  centesimal  composition  offers 
greater  or  less  variations,  as  may  be  seen 
by  comparing  the  specific  gravities  of  the  dif- 
ferent forms  of  phosphorus,  of  tin,  of  the  various 
acetic  aldehydes,  of  the  turpenes,  of  ice  and 
water,  of  quartz  and  tridymite,  of  aragonite  and 
calcite,  with  one  another,  and  even  of  different 
examples  of  calcite  among  themselves.  These 
differences  of  density  among  related  species, 
upon  which  the  writer  has  constantly  insisted, 
but  which  have  not  hitherto  received  the  atten- 
tion that  belongs  to  them,  are  evidently  con- 
nected with  the  greater  or  less  condensation  of 
matter  in  the  species,  or,  in  other  words,  with 


The  Law  of  Densities. 


loa 


polymerization.  Until,  however,  we  had  at- 
tained to  a  clear  conception  of  the  greatness 
of  the  condensation,  and  the  consequent  high 
equivalent  weight  of  such  species,  and  of  its 
relation  to  their  respective  specific  gravities ; 
and,  in  accordance  with  what  may  perhaps  be 
called  "the  law  of  densities,"  could  determine 
the  weights  of  liquids  and  solids  as  compared 
with  water,  it  was  impossible  to  give  to  these 
variations  in  specific  gravity  their  true  sig- 
nificance. 

§  64.  It  is  now  nearly  half  a  century  since 
Breithaupt,  by  greatly  multiplied  and  most 
careful  and  delicate  observations  of  the  genus 
Carbonites,  under  which  he  included,  with  other 
rhombohcdral  carbonates,  the  true  calcites  or 
calcium  carbonates,  distinguished,  among  these, 
numerous  species  and  sub-species,  marked  not 
only  by  variations  in  angular  measurements, 
in  lustre,  cleavage,  and  other  superficial  charac- 
ters, but  in  hardness  and  in  specific  gravity. 
Referring  the  student  for  details  to  the  second 
volume  of  Breithaupt's  Handbuch  der  Mineral- 
ogie  (1841),  it  will  be  sufficient  to  note  the 
names  and   the   densities  of   the  species   and 


'W 


104 


A  CJicmical  Philosophy. 


sub-species  of  rhombohedral  calcium-carbonate 
thus  defined  :  — 

Carbonites  archigonius 

Sub-species  C.  a.  levis     ....     2.690-2.710 


"  C.  a.  ponderosus   .     . 

Carbonites  paroicus 

Carbonites  cugnosticus 

Sub-species  C.  e.  epithematicus    . 

"  C.  e.  mediocris  .     .     . 

"  C.  e.  hypothematicus, 

Carbonites  diamesus 

Sub-species  C.  d.  polymorphus 

"  C.  d.  mediocris  .     . 

"  C.  d.  syngcneticus 

Carbonites  mero.xeiius 

Carbonites  haplotypicus 

Carbonites  melleus       


2734-2-7S4 
2.652-2.678 

2.700-2.708 
2.716-2.720 
2.720-2.730 

2.707-2.714 

2.721—2.727 

2.732-2.749 
2.689-2.705 
2.72S-2.729 
2.695-2.697 


Of  these,  C.  diamesus  is  by  far  the  most 
abundant  and  widely  diffused  species.  The 
hardness  of  these  calcites  varies  from  4^  and  4 
to  3I  on  the  scale  of  Breithaupt,  the  heavier 
being  the  harder  species ;  while  the  range  of 
densities  observed  is  from  2.652  to  2.754. 

§  65.  Reverting  to  the  law  of  densities 
already  set  forth,  and  taking  CCa03  =  99.89,  we 
arrive,  for  calcites  of  different  coefficients  of 
condensation,  and  for  aragonite,  at  the  densi- 
ties given  on  the  following  page. 


The  Law  of  Densities.  105 

It  is  evident  that,  while  the  Carbonites  paroi- 
CHs  of  Breithaupt  corresponds  nearly  in  density 
to  775(CCa03)  or  78o(CCOa3),  Carbonites  arc/ii- 
gonitis,  sub-species  a.  ponderosns,  attains  the 
density  of  8o5(CCa03),  the  other  calcites  cor- 
responding to  some  intermediate  term  ;  while 
that  of  86o(CCa03)  agrees  closely  with  the 
known  density  of  aragonite,  which  was  referred 
by  Breithaupt  to  another  genus,  and  according 
to  him  includes  Holocdritcs  haplotypicus  and 
H.  alloprismatieus. 

77S(CCa03) 2.6501 

78o(CCa03) 2.6672 

790(CCa03) 2.7014 

Soo{CCa03) 2.7356 

805(CCaO3) 2.7527 

86o(CCa03) 2.9408 

§  66.  The  question  here  arises  as  to  the 
value  of  the  polymeric  unit  in  these  calcium 
carbonates  with  densities  varying  from  2.652 
to  2.940.  In  case  of  acetic  aldehyde  and 
the  products  of  its  metamorphosis,  we  are 
enabled  by  vapor-densities  to  show  that  in  one 
case  we  have  to  do  with  C^jII^O,  and  in  another 
with  3(C2H40)  ;  while  in  the  turpentine  group 


1  ji'i 

>fc,...iili.  ml  1 

I'       il'.  'I ! 

It ; 


«i  ■" 


m 


1 06 


A  Chemical  Philosophy. 


Si  ii 


11 


I 


we  have  in  liquid  pentine  a  condensation  of 
CfiHg;  the  various  liquid  and  solid  di-pentines 
of  different  specific  gravities  and  boiling-points, 
being  in  like  manner  condensation-products 
of  2(C5Hg).  In  all  of  these,  also,  the  points  of 
fusion  and  of  ebullition  help  to  guide  us. 
When,  however,  we  come  to  deal  with  non- 
volatile solids,  like  calcite,  this  mode  of  deter- 
mination is  no  longer  open  to  us,  and  we  can- 
not say  whether  in  the  calcites  the  unit  is 
CCaOg  or  a  multiple  thereof  by  two,  five, 
or  ten ;  whether,  in  short,  the  formula  for 
the  calcite  of  density  2.7356  is  to  be  writ- 
ten 8oo(CCa03),  40o(C.jCa20o),  i6o(C5Ca50i5), 
or  8o(CioCaioOoo.)  Could  we  observe  sharply 
marked  intervals  in  the  density  of  various 
calcites,  corresponding  to  certain  multiples 
of  CCaOy,  they  would  furnish  the  data  for 
the  determination  of  the  problem.  But  in 
this  case  we  may,  from  the  absence  of  such 
intervals,  infer  the  probable  intervention  of 
the  principle  of  crystalline  admixtures  among 
isomorphous  species,  giving  rise  to  calcites  of 
intermediate  densities.  This  principle,  first 
clearly  applied  in  mineralogy  by  Von  Walters- 


M. 


The  Law  of  Densities. 


107 


hausen,  in  1853,  and  by  the  writer,  more  fully, 
and  independently,  in  1854  (6),  is  of  impor- 
tance within  the  limits  then  assigned  to  it ; 
though,  as  has  been  elsewhere  shown,  its 
application  has  been  misconceived  by  Tscher- 
mak,  who  some  years  afterwards  adopted  it.^ 

§  6"].  In  the  equation  p-^dz=.v,  it  will  be 
noted  that  the  value  of  /  is,  for  all  gaseous  or 
volatile  species,  deduced  directly  from  the 
observed  density  of  the  gas  or  vapor,  and 
represents  the  specific  gravity  of  such  species, 
hydrogen  gas  being  unity  ytX^  =  2.0) ;  the  same 
value,  for  non-volatile  species,  being  assumed  as 
corresponding  or  equivalent  thereto.  As  ex- 
amples, for  the  gaseous  carbon  dioxyd  CO2, 
we  find  /  =  44  (0=  16);  while  for  the  related 
silicon  dioxyd,  SiOj,  which  has  only  been  ob- 
served in  solid,  dense,  polymeric  forms,  such  as 
quartz  and  tridymitc,  we  assume />==  60,  which 
is  the  equivalent  weight  of  the  unknown  nor- 
mal gaseous  silicon  dioxyd.  For  calcite,  in 
like  manner,  we  assume  the  formula  CCaOa 
with  a  value  for/      100,  which  is  the  equiva- 


*  See  Mineral  Physiology  and  Physiography,  pp.  294-296, 


t 


342. 


m 

M 


■i- 


i,: 
II 


1 08 


Bli  ■  i  ' 


IK     . 


if        ] 


A  CJicmical  Philosophy, 


lent  weight  of  a  gas  or  vapor  less  dense  than 
that  of  amylic  alcohol. 

On  the  other  hand,  d  represents  the  density 
as  computed  for  liquids  and  solids ;  for  all  of 
which  that  of  water  at  4"*  is  taken  as  unity. 
The  relation  d :  /  is,  then,  that  of  the  density 
of  water  to  that  of  hydrogen  gas,  —  the  two  units 
of  specific  gravity, — or,  in  general  terms,  is 
that  of  liquid  and  solid  to  that  of  gas  and  vapor  ; 
while  V  shows  the  contraction  in  passing  from 
the  gaseous  to  the  liquid  or  solid  state  or,  in 
other  words,  is  the  reciprocal  of  the  coefficient 
of  condensation.  For  water,  in  which  the  value 
of  <:/=:i.ooo,  it  is  evident  that  d=v,  or,  in 
other  words,  that  the  reciprocal  is  identical 
with  the  gaseous  equivalent  weight.  We  have 
selected  water  as  the  first  example,  precisely 
because  its  specific  gravity  at  4° (=1.000)  is 
made  the  unit  of  density  for  all  liquids  and 
solids  ;  from  which  it  follows  that  the  equivalent 
weight  of  its  vapor,  p  (which  is  its  specific 
gravity,  H  =  1.000),  and  its  reciprocal  of  con- 
densation, V  (taking  now  the  corrected  equiva- 
lent weight  of  oxygen  =  15.9633)  are  alike 
17.9633.     In  the   case  of  ice,  however,  if  we 


The  Law  of  Densities.  i  qq 

take    d  =  o.c,iy^   wc    have    7' =19.5888.      We 
thus  obtain  :  — 


Water  =  1628(1120) 
Ice  =  1492(1120)   . 


162S  X  17.9633  =  29,244 
1492  X  19.5SSS  =  29,246 


Xing 


§  6S.    The  question  to  be   settled   in   fi 

the  equivalent  of  water  is  to  know  its  specific 
gravity  as  compared  with  that  of  the  same 
vohmie  of  hydrogen  gas,  or  of  steam,  at  a  com- 
mon temperature,  and  at  the  standard  pressure  ; 
for  which  experiment  has  accurately  determined 
the  weight  of  these  elastic  fluids.  These  rela- 
tions are  conveniently  shown  in  the  following 
table:—  " 


ill* 


Speciks. 

Hydrogen 

Steam 

Water 


Formula. 


Ha 
H2O 

i628(H20) 


Grams  i.\  i  Litrb  ' 
100°  and  760  mm.     I  Equivalent  Weight. 


0.06557a 

0.588940 

93^-780000 


2.0000 

I7.033 
29,244.0000 


It  will  be  remembered  that  the  contraction 
of  water  in  cooling  from  100°  to  4°  suffices 
to  raise  the  weight  of  the  litre  to  1000  grams. 

§  69.  To  give  a  farther  illustration :  the 
hydrocarbon    vapor  butane,    QIIjo  =  58,    con- 


no 


A  Chemical  Philosophy. 


P 


^ti« 


I 


I  I  : 


\wm  m^ 


denses  below  io°  to  a  liquid  having  at  o°  an 
observed  specific  gravity  of  0.600,  which  corre- 
sponds to  an  equivalent  weight  of  17,546,  com- 
pared with  water  as  29,244.  This  is  not  far  from 
302(C4Hio)  =  i7,5i6,  which,  at  its  point  of  ebul- 
lition, should  have  a  specific  gravity  of  0.5989. 
While  the  reciprocal  of  the  coefficient  of  con- 
densation for  steam,  ^=17.9633,  that  for  the 
gaseous  hydrocarbon  butane,  with  its  observed 
density,  is 

0.600 : 1. 000  : :  58  : 2/  =  96.66. 

The  value  v  in  the  formula  p-^d=  Vy  being 
the  reciprocal  of  the  coefificient  of  the  conden- 
sation suffered  by  the  gaseous  species  (or  the 
hypothetical  unit),  having  its  combining  weight 
(or,  in  other  words,  its  specific  gravity,  hydro- 
gen gas  being  unity)  represented  by  /,  in  pass- 
ing to  a  specific  gravity  calculated  for  water  at 
4°  as  unity,  and  represented  by  d.  We  may, 
therefore,  for  brevity,  designate  the  value  v  thus 
calculated  for  the  condensed  species  as  its 
reciprocal  number. 

The  density  of  solids,  as  of  liquid  species, 
should  for  comparison,  as  already  pointed  out  in 


The  Law  of  Densities.  jjj 

1853  (§  21),  be  taken  at  the  temperature  of  their 
formation,  or,  rather,  at  the  highest  tempera- 
ture  which  they  will  sustain  without  chemical 
change.      This    point    is,  however,   difficult    to 
fix   for   many   solids;   and,    as   the   coefficient 
of  expansion  varies  for  different  species,  and 
is  at  most  not  very  considerable,  we  take,  for 
the  present  purposes  of  study,  the  densities  of 
these  as  already  determined  at  ordinary  tem- 
peratures. 


i  hf'^ 


II'  •? 


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t 

I     >    ! 

K    ., 

Ill 

1 

i^' 


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■ 

] 

1 

i  i 
i 

CHAPTER   XII. 

A   HISTORICAL    RETROSPECT. 

§  70.  Of  the  fundamental  conceptions  em- 
bodied in  the  scheme  of  chemical  philosophy 
set  forth  in  the  preceding  pages,  there  are  two 
which  have  a  historic  interest  apart  from  the 
record  of  them  in  the  writer's  earlier  papers. 
These  are  :  (i.)  The  doctrine  of  high  equivalent 
weights  and  complex  formulas  for  all  liquid 
and  solid  species,  dependent  on  homogeneous 
integration  or  so-called  polymerization,  and  the 
direct  connection  of  this,  not  only  with  hard- 
ness and  insolubility,  or  chemical  indifference, 
but  with  specific  gravity ;  which,  it  has  been 
maintained,  varies  for  liquids  and  solids,  as 
well  as  for  gases  and  vapors,  directly  as 
the  equivalent  weight.  (2.)  The  doctrine 
that  liquefaction,  solidification,  vaporization, 
and   the   condensation   of    vapors,    as   well   as 

solution,  —  in   short,   all  changes   of   state   in 

112 


■A  Historica!  Retrospect.  j,, 

inorganic  species,  -are  cliemical  clun^-es      It 
■s  proposed  in  the  present  chapter  to  notice 
how  far  these   conceptions   have   been   enter- 
tamed,   and   to   what   extent   they  have   been 
advanced,  by  others  previous  to  or  durin-  the 
Penod    of    the    development    of    the    scheme 
wh:ch,   after   a  growth   of    thirty-eight    years, 
>s  now  for  the  first  time  resumed  and  stated  in 
a  completed  form. 

§  71.    The  conceptions   of    high   equivalent 

weights  and  of  polymerism  in  solid  species,  as 

deductions  from  thermo-chemical  studies,  were 

.ndicated  in  a  general  way  by  Favre  and  Silber- 

mann,  in  ,847,  whose  conclusions  were  cited  by 

he  wmer  in  his   more  detailed  exposition  of 

*7';";""«53(§-'°)-     Graham,  also,  clearly 

stated    the   notion    of  such   polymers,   though 

only  as  existing  in  solutions,  in  ,849,  as  a  de- 
cluct.on  from  his  studies  in  diffusion,  as  will  be 
shown  farther  on,  in  J  83.  Their  existence  was 
mamtamed  on  other  grounds,  by  the  writer,  for 

species,  both  complex  and 


elemental. 


in    1S48,   and   aG:ain 


and    1874,  as   already  recounted 
chapters. 


in    1853,   1867, 


in  preceding 


WA 


Vi^l 

■11 

Hi 

J  ^Hy 

1 

1 

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il 

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111 

j;  11! 

il  >; 


114 


^  Chemical  Philosophy, 


Spencer  Pickering,  who  does  not  seem  to  be 
aware  of  their  previous  history,  has  set  forth 
similar  views,  but  only  so  far  as  regards  poly- 
merism,  and  the  consequent  high  equivalent 
weights,  in  an  essay  on  The  Molecular  Weights 
of  Liquids  and  Solids,  in  1885.^  Therein,  after 
declaring  that  "  considerations  based  on  the 
crystalline  form  and  C'ther  physical  properties 
of  bodies  force  upon  us  the  conclusion  that 
liquid  and  solid  molecules  are  in  all  probability 
of  a  very  complicated  nature,  —  certainly,  more 
complex  than  gaseous  molecules,"  —  he  writes 
that  "  the  molecule  of  the  chemist  is  not  neces- 
sarily identical  with  the  molecule  of  the  physi- 
cist "  ;  and  supposes  that  chemical  molecules 
may  "  agglomerate  and  act  in  unison  as  regards 
certain  physical  forces."  That  such  an  **  ag- 
glomerate does  not  act  as  a  unit  towards  chemi- 
cal forces  "  shows,  according  to  Pickering,  that 
"  the  force  which  unites  the  individuals  consti- 
tuting it  is  not  chemical  force,  or  is  chemical 
force  of  such  a  weak  nature  "  as  to  oppose  no 


1  Proceedings  of  British  Association  for  the  Advancement 
of  Science,  in  the  Chemical  News  for  November  13  and 
20,  1885. 


A  Historical  Retrospect. 


i^i 


Iment 
and 


perceptible  resistance  to  ordinary  chemical 
agents.  We  have  here,  in  a  mechanical  form, 
and  in  the  language  of  the  atomic  hypothesis, 
a  reproduction  of  the  views  put  forward  by  the 
present  writer,  in  his  early  paper  of  1853,  as  to 
the  polymerism  and  high  equivalent  weight  of 
liquid  and  solid  species. 

§  72.  Pickering's  paper  was  presented  to  the 
British  Association  for  the  Advancement  of 
Science  in  1885,  at  the  same  time  with  one  by 
Guthrie  on  Physical  Molecular  Equivalents. 
He  therein  calls  attention  to  bodies  previ- 
ously studied  by  himself,  and  designated  by 
him  as  cryohydrates  and  subcryohydrates  ; 
which  may  be  described  as  very  fusible,  defi- 
nite crystalline  compounds,  containing  many 
portions  of  H2O  to  a  single  portion  of  a  salt  or 
alkaloid.  In  these  potassium  nitrate  is  said 
to  be  combined  with  44.6(HoO),  and  potassium 
sulphate  with  1 14.2 (HoO)  ;  while  diethylamine 
forms  a  well  defined  and  crystalline  compound 
with  27(H20).  Guthrie  conceives  that  in  these 
compounds  the  "  constituents  arc  not  in  the 
ratio  of  any  simple  multiples  of  their  chemical 
equivalents."     A  similar  conception  is  by  him 


i 


WM 


.1 


II' ;■ 


,  t: 

i 


ii 


ii6 


A  Chanical  Philosophy. 


•:1 


^V\ 


extended  to  certain  metallic  alloys,  which,  from 
their  ready  fusibility,  he  designates,  like  these 
cryohydrates,  as  "eutectic."  ^ 

§  'j'}^.  On  the  other  hand,  Messrs.  Tilden  and 
Shenstonc,  in  their  studies  of  the  great  solu- 
bility in  water  of  salts  when  near  their  melting- 
points,  have  described  compounds  which,  unlike 
the  cryohydrates,  are  homogeneous  liquids,  con- 
taining, in  the  case  of  somewhat  fusible  com- 
pounds, like  silver  nitrate  and  benzoic  acid, 
very  small  proportions  of  water  ;  from  which 
the  experimenters  are  led  to  conjecture  for 
bodies  an  indefinite  solubility  in  water  under 
proper  conditions  of  temperature  and  pressure.^ 
It  is,  however,  easy  to  understand  from  the 
high  equivalent  weights  of  such  dense  liquids 
(which  from  their  viscosity  are  probably  col- 
loidal) that  compounds  with  water  may  exist 
in  which  the  proportion  of  the  latter,  though 
definite,  is  so  small  a  fraction  that  it  would  be 
neglected  in  the  ordinary  processes  of  analysis. 


m 


*  Fred.  Guthrie,  on  Physical  Molecular  Equivalents,  Na- 
ture, Nov.  6,  1885 ;  also  on  Eutexia,  L.,  E.,  and  D.  Philosoph- 
ical Magazine,  1884,  xvii.  262. 

2  Philosophical  Transactions,  1884;  part  I.,  pp.  23-36. 


A  Historical  Retrospect. 


117 


)ugh 

be 

^sis. 


I,  Na- 

3oph- 


The  subject  of  these  compounds  is  discussed 
by  the  writer  in  his  Mineral  Physiology  and 
Physiography,  pp.  221-222,  and  also  p.  245,  note; 
where  the  geological  significance  of  small  por- 
tions of  water  in  combination  under  high  pres- 
sure in  molten  silicated  rocks  is  insisted  upon. 

These  two  cases  of  apparently  homogeneous 
compounds,  — on  the  one  hand,  liquids  existing 
at  high  temperatures,  with  very  small  propor- 
tions, and,  on  the  other,  solids  at  low  tempera- 
tures, with  very  large  proportions  of  water,  — 
are  like  illustrations  of  the  complex  formulas 
and  high  equivalent  weights  which  we  have  so 
long  maintained.  So  far  from  being,  as  con- 
jectured by  Pickering,  and  by  Guthrie,  com- 
pounds in  some  sense  outside  of  the  domain 
of  chemistry,  their  constitution,  as  was  said  of 
similar  cases  in  1867,  does  not  present  "a 
deviation  from  the  law  of  definite  proportions," 
but  "  is  only  an  expression  of  that  law  in  a 
higher  form."  (10.) 

§  74.  A  broader  view,  and  a  more  complete 
comprehension  of  the  great  problem  under  con- 
sideration, is  shown  in  a  remarkable  paper  by 
Professor  Louis  Henry,  of  the  Catholic  Univer- 


i 

iilU 


ilii 


ii8 


A  Chemical  Philosophy. 


i  t 


ttii 


i  \ 


sity  of  Louvain,  published  in  August,  1885, 
on  The  Polymerization  of  Metallic  Oxyds,^  in 
which,  though  without  any  reference  to  the 
present  writer's  publications,  will  be  found 
developed  alike  the  conception  of  polymerism 
in  liquid  and  solid  species,  and  the  dependence 
thereon,  not  only  of  hardness  and  chemical  in- 
difference, but  of  specific  gravity.  In  fact, 
most  of  the  important  conclusions  announced 
in  the  author's  publications  from  1848  to  1867, 
inclusive,  arc  set  forth  in  the  language  of  the 
atomic  hypothesis  by  Henry  in  his  recent 
paper. 

He  explains  the  generation  of  complex  oxyds 
by  the  union  of  several  equivalents  of  hydrates, 
and  the  successive  elimination  of  equivalents 
of  water,  as  caught  by  Adolphe  Wurtz  in 
i860,  in  discussing  the  origin  of  polysilicates.^ 

^  London,  Edinburgh,  and  Dublin  Philosophical  Magazine 
(5)  XX.  81-117.  This  essay  escaped  the  notice  of  the  writer 
until  October,  18S6;  otherwise  it  would  have  been  noticed  in 
referring  in  Science  for  Sept.  10,  1886,  to  the  paper  of  Spencer 
Pickering,  when  the  mode  of  fixing  the  value  of  the  coeffi^ 
cient  of  condensation  for  liquids  and  solids  was  first  set  forth, 
as  shown  in  §  46. 

^  See  the  author'^  Mineral  Physiology  and  Physiography, 
p.  298. 


A  Historical  Retrospect. 


119 


it       P'     -. 

li    r    !| 


While  the  chlorids  of  carbon,  silicon,  titanium, 
and  aluminium  are  species  readily  converted 
into  vapors  of  normal  density ;  and  while  car- 
bonic dioxyd  is  a  gas,  only  changed  into  a 
liquid  form  under  great  pressure,  the  oxyds  of 
silicon,  titanium,  and  aluminium  are  fixed  and 
solid  bodies,  of  greater  or  less  density  and  hard- 
ness, and  are  polymers  of  the  elemental  oxyds. 
These,  in  their  more  highly  condensed  forms, 
"  show  a  greater  resistance  to  the  action  of 
chemical  agents  than  in  their  former  condition, 
in  bome  cases  even  entirely  resisting  the 
action  of  acids  and  alkalies."  Henry  concludes 
that  "  the  true  oxyds,  which  are  really  compara- 
ble with  the  chlorids,  are  unknown,  and  that 
we  possess  only  polymers  of  these,  (RO,r);/." 
The  condensation  of  these  varies,  "  but  appears 
to  attain  its  maximum  in  certain  fixed  and  very 
infusible  oxyds,  such  as  silica,  alumina,  etc. 
.  .  .  This  enormous  condensation  of  their  mole- 
cules may  possibly  be  the  cause  of  the  greater 
resistance  which  they  offer  to  the  action  of 
simple  chemical  agents,  such  as  hydrogen, 
carbon,  sulphur,  etc  " 

§  75.   Henry  next  suggests  that  "  the  specific 


b 


I20 


A  Chemical  Philosophy. 


\i    i 


gravity  of  a  solid  body  doubtless  depends  in  a 
great  measure  on  the  state  of  aggregation,  and 
is  also  intimately  connected  with  the  composi- 
tion of  the  body,  and  the  size  of  the  molecular 
weight "  ;  adding  "  the  density  then  is,  to  a  cer- 
tain degree,  a  function  of  the  molecular  weight." 
Having  reached  this  point,  he  proceeds  as  fol- 
lows :  "What,  now,  is  the  true  value  of  the 
coefficient  n  of  polymerization  ?  What  is  the 
real  molecular  formula  of  these  polymeric 
oxyds  ?  These  questions  arc,  doubtless,  of 
great  interest ;  but  it  should  be  stated  at  once 
that  it  is  absolutely  impossible  to  give  a  direct 
answer.  I  do  not  know  of  any  fact  which 
would  allow  us  to  assign  an  absolute  value 
to  the  coefficient  ?i  of  polymerization.  ...  So 
far  as  facts  will  permit  a  conclusion,  we  may 
affirm  that  in  most  cases  this  number  is  very 
high,  although  different  for  different  oxyds." 

§  ^6.  The  problem  of  the  value  of  the  con- 
densation in  passing  from  the  gaseous  to  the 
solid  state,  as  presented  by  Henry,  in  1885, 
is  thus  precisely  that  put  forth  by  the  present 
writer  in  1853,  when  he  asked  for  a  determina- 
tion of  the  coefficient  of  condensation,  and  at 


Mfi 


A  Historical  Retrospect. 


121 


the  same  time  affirmed  more  positively  than 
is  done  by  his  successor  in  1885,  that  the 
density  in  liquids  and  solids  varies  directly 
as  the  equivalent  or  so-called  molecular  weight. 
(§  41.)  The  direct  relations  of  this  condensa- 
tion to  hardness,  and  to  chemical  indifference, 
were,  moreover,  as  we  have  seen  in  preceding 
chapters,  clearly  formulated  by  the  present 
writer,  in  1863,  and  even  in  1848  were  sug- 
gested in  the  case  of  the  forms  of  phosphorus, 
etc.  The  problem  of  fixing  the  coefficient  of 
condensation  thus  put  forth,  although  not  an- 
swered, in  1853,  and  again  propounded,  and 
declared  unsolved,  by  Henry,  in  1885,^  has,  it 
is  believed,  been  successfully  resolved  in  the 
preceding  chapters. 

1  Henry  has  given,  in  his  paper,  the  following  valuable 
classification  of  oxyds,  considered  with  reference  to  polymeri- 
zation :  — 

A.  Normal  oxyds,  as  SO 2,  CO2,  NO. 

B.  Polymerized  oxyds,   consisting   of  //  molecules  of    the 

normal  oxyds  united. 
I.  Volatile  oxyds.  totally  depolymerized  by  heating,  and 
converted  into  the  normal  oxyd. 
a.    Completely    depolymerized    on    volatilization,  and 
yielding  a  vapor  of   normal    density,  as  S()3,  OSO4, 
methylene  oxyd  (CII^O);/,  metaldehydc(C2ll40)3. 


m 


m    ) 


122 


A  Chemical  Philosophy. 


||ll 

L 


§  TJ.  We  must  here  notice  an  essay  which 
appeared  in  1876,  entitled  Geometrical  Chem- 
istry, by  Prof.  Henry  Wurtz/  of  New  York,  in 
which  he  insists  on  the  great  significance  of 
density,  and  of  the  variations  therein,  as  ob- 
served in  liquid  and  solid  species.  He  asserts 
(evidently  excepting  the  temporary  changes 
which   depend   on   variations    in    temperature) 

b.  Incompletely  depolymerized  at  the  moment  of  volatil- 
ization, the  process  being  completed  progressively,  as 
the  temperature  rises.  The  vapor-density  of  these 
gradually  diminishes  with  increase  of  temperature,  up 
to  a  certain  point,  beyond  which  it  becomes  constant, 
and  corresponds  to  the  normal  oxyds;  N2O4,  fatty 
acids,  and  paraldehyde,  which  last,  at  low  tempera- 
tures, corresponds  to  (C 2 1140)3,  but  at  higher  tem- 
peratures becomes  (C2H4O).  [In  this  category,  we 
may  place  the  elemental  species  iodine,  bromine,  and 
chlorine.] 

2.  Volatile  oxyds,  incompletely  depolymerized  .it  tempera- 
tures to  which  they  have  been  subjected,  as  (AsjOjja. 
The  volatilization  of  solid  arsenious  oxyd,  at  200°, 
without  fusion,  is  the  change  of  (As203)«  into  (As203)2. 

3.  Oxyds  not  capable  of  depolymerization. 

a.  Fixed  oxyds,  like  SiOa,  MgO,  AI2O3,  Fe203' 

b.  Oxyds  volatile  or  decomposed  by  heat,  as  ^IgO, 
AgjOi  MnOa,  CrOs  ;  also,  organic  oxyds  decomposed 
by  heating. 

^  Geometrical  Chemistry,  by  Henry  Wurtz,  pp.  73,  reprinted 
from  the  American  Chemist  for  March,  1S76. 


w 


;t    i  I 


A  Histot  ical  Retrospect. 


123 


that  "  change  of  volume  or  of  density  in  a 
specific  liquid,  or  a  specifically  solid  body, 
whether  elementary  or  compound,  —  even  when 
occurring  without  change  of  crystalline  system, 
—  is  an  infallible  indication  of  change  of  molec- 
ular structure,  and,  consequently,  of  chemical 
nature."  Without  attempting  to  grapple  with 
the  problem  of  the  direct  relation  of  density  in 
such  bodies  to  their  equivalent  weights,  as 
propounded  by  the  writer  in  1853,  and  again 
by  Louis  Henry  in  1885,  Wurtz,  nevertheless, 
sought  to  frame,  in  accordance  with  the  atomic 
hypothesis,  an  explanation  of  the  densities  of 
liquid  and  solid  species.  To  this  end  he  con- 
structed for  these  chemical  formulas,  which, 
from  their  frequent  complexity,  seem  to  imply 
polymerism  and  high  equivalent  weights.  We 
find,  however,  on  farther  examination,  that  the 
weights  adopted  by  him  do  not  represent  those 
deduciblc  from  these  formulas,  but  are  the  sim- 
plest combining  numbers,  —  hydrogen  being 
unity,  —  multiplied,  however,  by  1000,  to  avoid 
fractions. 

§  78.   Regarding  chemical  species  as  built  up 
by  the  agglomeration  or  juxtaposition  of  ele- 


III 


^ 


\li 


I 


124 


A  Chemical  PJdlosophy. 


mental  molecules,  Wurtz  supposes  that  similar 
molecules  entering  into  a  compound  may  pos- 
sess unlike  volumes,  and  to  this  attributes  the 
variations  in  the  density  of  isomeric  species. 
The  elemental  molecules  in  his  hypothesis  have 
different  diameters,  represented  by  integers 
from  12  to  40,  the  cubes  of  these  numbers 
being  the  volumes  of  the  molecules.  These 
diameters  for  the  metals,  hydrogen,  and  phos- 
phorus, are  very  variable  ;  while  for  sulphur, 
chlorine,  bromine,  and  iodine,  they  are  pretty 
constantly  28  or  24 ;  the  latter  being  the  diame- 
ter for  chlorine  in  chlorates  and  in  all  monad  or 
dyad  chlorids.  This  being  conceded,  he  ap- 
plies to  any  liquid  or  solid  species  the  formula 
p-i-d=.z\  and  thus  gets  what  has  been  called 
its  molecular  volume,  multiplied,  like  its  com- 
bining weight/',  by  1000.  Taking  now  as  an  ex- 
ample, liquid  chlorhydric  acid,  with  a  combining 
weight  for  H CI  =/=  36,500,  and  an  observed 
density  of  1.27,  we  get  2^=28,516.  Deducting 
from  this  the  volume  of  €1  =  24^—13,824, 
there  remains  for  the  volume  of  H  =  14,692, 
which,  as  he  notes,  is  "almost  identical  with 
the  mean  figure  between  24^  and  25V'  whence 


A  Historical  Retrospect. 


125 


he  concludes  that  "  liquid  hydrochloric  acid  must 
be  H2CI2,  containing  H  with  the  two  diameters 

24  and  25,"  and  that  its  "  volumic  or  molecular 
formula"  must  be  represented  accordingly. 
But  the  volume,  as  deduced  from  this  formula 
=  (24^  X  3)  +  (25^)  =  57,097,  is,  as  near  as  the 
method  will  admit,  double  the  value  of  v ;  so 
that  the  "  molecular  formula,"  as  understood  by 
Wurtz,  corresponds  not  to  H2CI2,  with  two 
diameters  for  the  two  molecules  of  H2,  but  to 
a  mean  between  HCl  with  H  =  24  and  HCl 
with  H  =  25. 

§  79.  In  like  manner,  sodium  chlorid  with 
density  2.25  is  represented  by  NaCl,  in  which 
the  diameter  of  the  molecule  of  sodium  =  23; 
while  that  with  density  2.18  is  supposed  to  be 
represented  by  NajCla  ,in  which  we  have  so- 
dium with  the  two  diameters  of  23  and  24. 
The  same  chlorid  with  density  2.05  is  Na2Cl2, 
having  for  sodium  the  two  diameters   24   and 

25  ;  potassium  chlorid,  with  density  2.01,  being 
K2CI2,  with  the  diameters  28  and  29  for  the  two 
potassium  molecules.  Similarly,  phosphorus 
with  density  1.797  is  supposed  to  consist  of 
one  molecule  with  a  diameter  of  25,  and  five 


!  f^ 


Ur  i 


^ 


ir 


iiA 


126 


^  Chemical  Philosophy. 


molecules  with  a  diameter  of  26 ;  while  metal- 
loidal  phosphorus,  with  density  2.297,  includes 
one  molecule  of  23  and  four  of  24.  In  these 
cases  of  apparently  complex  formulas,  however, 
as  in  the  case  of  chlorhydric  acid,  the  value 
adopted  for/  is  not  a  multiple,  but  the  number 
representing  NaCl  or  P.  Thus,  for  metal- 
loidal  phosphorus,  described  above  as  made  up 
of  five  molecules  of  P,  and  with  a  density  of 
2.297,  we  have,  with /=:  31,000,  a  value  for  v 
=  13,495.  But  (248)  X  4  +  (23')  =  67,463  "^ 
5  =  2^=13,492;  while/ -^- £^=:^=:  2.297,  the 
observed  density. 

§  80.  By  thus  adding  together  at  pleasure 
the  cubes  of  any  number  of  integers  between 
1 2  and  40,  and  dividing  the  sum  by  this  num- 
ber, in  order  to  obtain  a  mean  value  wherewith 
to  divide  the  combining  weight  of  the  species, 
it  is  evident  that  we  may  arrive  at  a  near 
approximation  to  the  value  of  v  as  found  for 
any  observed  density  of  a  given  species,  and 
therefrom  get  by  calculation  a  closely  corre- 
sponding density.  The  assumption,  however, 
that  V  represents  the  volume  of  the  composite 
molecule  generated  by  the  putting  together  of 


A  Historical  Retrospect.  127 

elemental  molecules  is,  as  we  have  sought   to 
show,  unfounded  ;   while  the  other  assumption 
that  the  diameters  of  these  are  represented  by 
the    integers    above    indicated    is    gratuitous. 
There  is  no  apparent  relation  in  the  nature  of 
things  between  these  integers  and  the  amount 
of   contraction    suffered,  for   example,    by   the 
gaseous  species  HCl,  with  a  specific  gravity  = 
36.5  (hydrogen  being  unity),  in  passing  into  the 
liquid  species,  having  a  specific  gravity  of  1.27 
(water  being  unity) ;   and  we  must  regard  the 
calculations  of  density,  and  of  chemical  consti- 
tution, arrived  at  by  the  above  method  as  illu- 
sory and  essentially  fallacious. 

Moreover,  as  we  have  elsewhere  said,  while 
calling  attention  to  the  importance  of  the 
study  of  the  densities  of  liquids  and  solids,  so 
well  insisted  upon  by  Wurtz,  "  the  conception 
that  the  chemical  elements  enter  as  such  into 
combination,  and  there  retain  their  volumes, 
appears  to  be  inadmissible  in  chemical  philoso- 
phy." (16.) 

§  81.  Proceeding  now  to  consider  the  his- 
tory of  the  conception  that  all  changes  of  state, 
such  as  solution,  fusion,  solidification,  vaporiza- 


Hi 


PI" 


I 


128 


A  CJicmical  Philosophy. 


tion,  and  the  condensation  of  vapors,  are  chemi- 
cal in  their  nature,  we  arc  led  to  review  the 
phenomena  of  gaseous  and  liquid  diffusion,  as 
definitely  set  forth  by  Graham,  in  1849.  The 
diffusion  of  salts  from  their  solutions  into  pure 
water  was  by  him  compared  to  the  diffusion  of 
gases,  and  to  the  evaporation  of  liquids  into  the 
atmosphere.  "  The  analogy  of  liquid  diffusion 
to  gaseous  diffusion  is  borne  out  in  every  char- 
acter of  the  former  which  has  been  examined," 
according  to  Graham  ;  while  diffusion  was 
farther  said  to  be  "  a  property  of  a  fundamen- 
tal character,  upon  which  other  properties 
depend,  like  the  volatility  of  substances," 
"The  number  of  species  that  are  soluble, 
and  therefore  diffusible,  appears  to  be  much 
greater  than  the  number  of  volatile  bodies." 
**  Separations,  both  mechanical  and  chemical 
(decompositions),  are  produced  by  liquid,  as 
well  as  by  gaseous  diffusion."  "Liquid  diffu- 
sion, as  well  as  gaseous  evaporation,  may  pro- 
duce chemical  decompositions."  "The  diffu- 
sion of  a  salt  appears  to  try  its  tendencies  to 
decomposition  very  severely." 

§  82.  The  above  citations  are  from  Graham's 


A  Historical  Retrospect. 


129 

Bakerian  Lecture  on  Diffusion,  in  ,849.     From 
h.s  extended  studies  of  this  subjeet  up  to  that 
date,  he  was  led  to  conclude  that  there  exist 
groups  of  equi-diffusive  substances,  which  coin- 
CKle,   m   many  cases,    with    the    isomorphous 
groups  but,  on  the  whole,  are  more  comprehen- 
s.ve   than   the   latter.      Moreover,   for  several 
groups  of  salts,  it  was  found  that  the  squares 
of  the  t,mes  of  equal  diffusion  from  solutions  of 
the  same   strength  stand  to  each  other  in   a 
simple  numerical  relation.     The  squares  of  the 
times  of  equal  diffusion  of  gases,  as  Graham 
had  shown,  are  to  one  another  in  the  ratio  of 
the,r   densities.      From   this,   by  analogy,   ,,e 
■n  erred   that  the   molecules   of  these   several 
sa  ts  as  they  exist  in  solution,  possess  densities 
which  are  to  one  another  as  the  squares  of  their 
times   of    diffus.on.      These    he    called    their 
solut,on-dcnsities.  which,  for   the   sulphate,    ni- 
trate,  and  hydrate  of  potassium,  for  example 

were  found  to  be  as  4 :  ,  ■ ,  •  teinc  ,1,. 
,  t  ■  -  .  i ,  oeing  the  squares 

of  2,  1.4,43  and  I,  the  numbers  representing 
the  relative  times  occupied  in  the  diffusion  of 
equal  weights  of  these  three  species, 
§  H    Graham   thus  constructed   a   scale   of 


.    ^1 


■ 


ii 


I30 


A  Chemical  Philosophy. 


(( 


solution-densities  which,  in  his  words,  "are 
suggested  by  the  different  diffusibi  .  of 
salts,  and  to  which  alone,  guided  by  the  analo- 
gies of  gaseous  diffusion,  we  can  refer  these 
diffusibilities.  Liquid  diffusion  thus  supplies 
the  densities  for  a  new  kind  of  molecules,  but 
[supplies]  nothing  more  about  them."  "The 
fact  that  the  relations  in  diffusion  of  different 
substances  refer  to  equal  weights  of  these  sub- 
stances, and  not  to  their  atomic  weights  or 
equivalents,  is  one  that  reaches  to  th  very 
bases  of    molecular   chemistry.      The  Hon 

most  frequently  perceived  is  that  of  equality. 
In  liquid  diffusion  we  appear  to  deal  no  longer 
with  chemical  equivalents,  or  the  Daltonian 
atoms,  but  with  masses  even  more  simply 
related  than  these  in  weight.  Founding  still 
upon  the  chemical  atoms,  we  may  suppose 
that  they  can  group  themselves  together  in 
such  numbers  as  to  form  new  and  larger  mole- 
cules, of  equal  weight  for  different  substances  ; 
or,  if  not  of  equal  weight,  of  weights  which 
appear  to  have  a  simple  relation  to  each  other. 
It  is  this  new  class  of  molecules  which  appears 
to  play  a  part  in  solubility,  and  in  liquid  diffu- 


A  Historical  Retrospect. 


i^  not   the   ato^s  of  ehe.ica,  Jb' 

The  reader  can  judge  how  far  this  generah'za. 
;on  of  Graham,  as  to  an  apparent  polymeriz-. 

relative   rates    of    aqueous    diffusion,   led   the 
-mer  naturally  to    the    broader  doctrine   o 
polymerization  alike  in  liquid  and  solid  specie 
as  put  forth  by  him  in  ,853,  ,„,  ^„^^^  .^^^^^ 
Here,  also,  .s  the  view,  reiterated  by  Spence; 

cJesTTh^^''^^^''"""^''''^^^^'-" 
c«  es  by  th.  union  of  many  chemical  molecules. 

S  84.   Co.  -mumg   his   studies    in    diffusion 

Graham  wrote  farther,  in  ,86,....  So  similarTn 
c  aracter  to  volatility  is  the   diffusive  pow 

P    sessed  by  all  liquid  substances,  that  we  may 

a,    csT  """"  ^  *"  "'  ^"^"^S"-  analyt,- 

cal  resources  to  arise  from  it  "      o 

degree  of  diffusible  mobility  exhibited^d-ffi 
nt  s  b  tances  appears  to   be  as  wide'as  t 

UwIsn''"       """■"■"    °f  P°'----'  hydrate 
"  "'^  "'^"  ^^'^  ">at  it  has  double  the  velocity 


i 


132 


A  Chemical  Philosophy. 


ft  I 


of  diffusion  of  potassium  sulphate,  and  this 
double  that  of  sugar,  alcohol,  and  magnesium 
sulphate  ;  all  of  which,  howc  'er,  as  regards  diffu- 
sion, he  compared  to  the  more  volatile  bodies  — 
the  comparatively  fixed,  or  non-volatile  bodies, 
being  represented  by  the  colloids.  Of  these  he 
remarks  that,  '*  while  the  rigidity  of  crystalline 
structure  shuts  out  external  impressions,  the 
softness  of  the  gelatinous  colloid  partakes  of 
fluidity,  and  enables  the  colloid  to  become  a 
medium  for  liquid  diffusion,  like  water  itself." 
"  Colloids  are  characterized  by  mutability." 
"Their  existence  is  a  continual  metastasis."^ 
His  conjecture  that  colloids  have  perhaps  a 
higher  equivalent  weight  than  crystalloids,  has 
apparently  no  substantial  basis.  We  have 
elsewhere  (§  30)  noticed  the  earlier  observa- 
tions of  Breithaupt  on  colloids,  both  of  aqueous 
and  igneous  origin,  called  by  him  porodic  bod- 
ies. The  relation  of  such  substances  to  the 
process  of  diffusion  was,  however,  unknown 
to  Breithaupt,  and  was  discovered  by  Graham. 

'  The  papers  of  Graham  above  cited,  published  in  the 
Philosophical  Transactions  for  1850  and  1861,  are  reprinted  in 
his  Chemical  and  Physical  Researches,  1876,  pp.  444-600. 


A  Historical  Retrospect.  133 

§  85.  As  early  as   1847,  in  a  paper  already 
noticed    (§  20),    Favre   and    Silbermann  1    had 
described  the  loss  and  fixation  of  water  in  the 
efflorescence  and  deliquescence  caused  by  the 
action   of  the   atmosphere   on   certain   bodies 
and   the   precipitation    by   heat   of    anhydrous' 
sodium    sulphate    from   its    aqueous    solution 
as  alike  chemical  processes.     As  facts  in  the 
same  order,  Graham  had  shown,  in   1849,  that 
both  liquid  and  gaseous  diffusion  may  produce 
chemical    decomposition,    and    had    compared 
these  processes   to   volatilization.     It  was   re 
served  for  Henri  Sainte-CIaire  Deville  to  take 
another  step  in  this  new  way  by  his  studies  in 
chemical  dissociation,  the  publication  of  which 
was   begun   in    1857,    when   he  described    the 
decomposition  by  heat  of  potassium   hydrate 
and  showed  the  partial  decomposition  of  water 
at  temperatures  much  lower  than  had  hitherto 
been  suspected.2     In  i860,  he  said  of  dissocia- 

n  assim- 


tion 


ilating  these  phenomena  to  those  of  the  ebulli- 
.os!-^7'"  ''™'"'  "=  '^^^'-  0"  =-■-«.  .54;.  «iv. 

^  Ibid.,  1857;  xlv.  857. 


^Jll,l 


134 


A  Chemical  Philosophy. 


.»»■■' 


tion  of  liquids,  or  the  vaporization  of  non-lique- 
fiable  solids."  ^  The  action  of  metallic  points 
in  promoting  ebullition  was  then  by  him  com- 
pared to  that  of  manganese  oxyd  in  fused  potas- 
sium chlorate. 

§  ^6.  Returning  to  the  subject  in  1863,^ 
in  farther  discussion  of  the  decomposition 
of  water  by  heat,  Deville  wrote  :  "  The  com- 
parisons between  the  effects  of  cohesion  and 
of  affinity,  which  are  so  instructive  for  liquid 
and  solid  bodies,  are  maintained  in  the  in- 
verse phenomena  of  volatilization  and  de- 
composition. Admitting  this  comparison,  we 
see  that  the  phenomena  of  the  decomposition 
of  bodies  at  a  relatively  low  temperature,  or 
dissociation,  corresponds  to  the  vaporization  of 
a  liquid  at  a  temperature  below  its  boiling- 
point  ;  and  that  the  quantity  of  the  body  disso- 
ciated at  a  given  temperature  will  be  propor- 
tional to  its  tension  of  dissociation  expressed 
in  millimetres  of  mercury ;  as  the  quantity  of 
vapor  formed  above  a  liquid  at  a  given  tempera- 
ture is  proportional  to  the  maximum  tension  of 

^  L.,  E.,  and  D.  Philos.  Mag.,  i860 ;  xx.  457. 

2  Comptes  Rendus  de  I'Acad.,  1863;  Ivi.  195-201. 


A  Historical  Retrospect. 


135 


its  vapor."  "  The  phenomenon  of  the  decompo- 
sition of  bodies  is  in  all  respects  similar  to  that 
of  the  ebullition  of  liquids,  the  principal  charac- 
ter of  which  is  the  invD "lability  of  their  tem- 
perature, whatever  the  intensity  of  the  source 
of  heat,  provided  the  pressure  is  constant." 

Thus,  while  looking  upon  the  cohesion  of 
liquids,  and  their  volatilization,  as  phenomena  in 
some  way  distinct  from  those  of  chemical  com- 
bination and  decomposition,  Deville  was  forced 
to  conclude  that  they  are  governed  by  the  same 
la"vv& ,  involving  a  change  of  state  and  of  ther- 
mic relations,  and  subordinated  to  the  same 
conditions  of  temperature  and  of  pressure. 

§  87.  In  considering,  in  1863,  the  phenomena 
of  dissociation,  as  then  lately  studied  by  Pdbal 
for  ammonium  chlorid,  and  by  Wanklyn  and 
Robinson  for  sulphuric  acid  and  phosphorus 
chlorid,  Deville  recalls  the  phenomena  of  diffu- 
sion, as  studied  by  Graham  in  aqueous  solu- 
tions, and  adds:  We  have  here  "a  veritable 
force  which  leads  to  the  separation  of  elements, 
and  which  must  not  be  neglected  in  the 
explanation  of  the  phenomena  described  by 
Messrs.   P^bal,  Wanklyn,  and  Robinson,  since 


iil 


136 


A  Chemical  Philosophy. 


il    ! 


the  same  reasoning  applies  to  aqueous  diffu- 
sion and  to  diffusion  in  gases  or  vapors  which 
have  different  diffusive  powers  or  rates  of 
transpiration.  The  new  agent  of  decomposi- 
tion introduced  by  Graham  is  so  energetic  that 
we  can  no  longer  designate  as  spontaneous  the 
decompositions  produced  under  its  influence."  ' 

Still  later,  in  1865,^  Deville  wrote  of  chemical 
combination  :  "  We  have  no  knowledge  of  what 
combination  is ;  we  do  not  even  know  what 
distinguishes  it  from  solution ;  but  we  can 
characterize  it  as  a  change  of  state,  marked 
by  new  physical  or  chemical  properties,  serving 
to  distinguish  combination  from  simple  mixture. 
This  change  of  state  is  most  generally  accompa- 
nied by  a  disengagement  of  latent  heat,  which 
approximates  combination  to  the  condensation 
of  vapors  ;  but  it  may  also  be  accompanied  by 
an  absorption  of  latent  heat,  or  cooling,  as  for 
explosive  bodies  like  NO  and  NClj,  which  are 
formed  by  combination  in  the  nascent  state, 
and  give  off  heat  in  decomposing ;  so  that  the 


1  Comptes   Rendus  de  I'Acad.,   April   20,   1863 ;    Ivi.  pp. 

729-733- 

2  Bulletin  de  la  Society  Chimique;  iii.  15. 


^  Historical  Retrospect.  137 

disengagement  of  heat,  the  production  of  cold, 
or  the  absence  of  thermometric  effect,  proves 
nothing  for  or  against  the  fact  of  combination." 
§  ^^.  Thus   we   have   seen   that   Favre  and 
Silbermann,  in  1847,  regarded  the  separation  of 
salts   from   solutions   by  changes   of  tempera- 
ture,  the  fixation  of   aqueous  vapor  from  the 
atmosphere  by  certain  bodies,  and  its  loss  by 
others,  as  all  alike  chemical  changes.     Graham, 
in  1849,  insisted  upon  the  likeness  of  the  vola- 
tilization of  liquids  to  gaseous  and  liquid  diffu- 
sion, and  asserted  that  all  of  these  processes 
may  produce  chemical  decompositions.     Henri 
Sainte-CIaire    Deville,    in     1857 -1863,     while 
adopting    Graham's    conclusions,    farther    de- 
clared  that    the   decomposition    of    bodies   by 
heat  is   in  all   respects   similar  to  that  of  the 
evaporation  of   liquids,  and  is  subordinated  to 
the  same  laws. 

§  89.  The  writer,  who  enjoyed  the  great  advan- 
tage of  personal  intercourse  alike  with  Graham 
and  with  Sainte-Clairc  Deville,  and  conversed 
with  both  of  them  on  the  subjects  here  dis- 
cussed, had  with  the  latter,  whom  he  had  then 
long  known,  frequent  conferences   during   the 


Hi 


ii, 


i 


138 


A  Chemical  Philosophy. 


itl 


i-'  \ 


spring  and  summer  of  1867,  at  his  laboratory, 
at  the  Ecole  Normale,  in  Paris,  when  the  rela- 
tions of  the  homogeneous  volatilization  of  liquids 
and  solids  were  compared  with  the  phenomena 
of  dissociation.  Graham,  whom  I  had  known 
since  1856,  was  there  for  a  few  days  our  com- 
panion ;  and  to  both  of  these  I  maintained,  in 
accordance  with  the  views  in  my  paper,  then 
recently  published  (10),  that  the  liquid  and 
solid  bodies,  water  and  ice,  are  polymeric  spe- 
cies, distinct  from  aqueous  vapor,  their  conver- 
sion into  which  is  a  process  of  depolymerization, 
or  homogeneous  disintegration ;  a  conclusion 
admitted  by  both  Graham  and  Deville  to  be 
a  logical  deduction  from  their  own  premises, 
as  has  already  been  shown.  The  views  which 
I  have  advocated  in  various  publications  since 
1853,  and  in  the  preceding  chapters,  with 
regard  to  the  constitution  of  liquids  and  solids, 
their  high  equivalent  weights,  and  all  their 
relations  to  gases  and  vapors,  appear  to  be  in 
fact  but  the  legitimate  and  necessary  conse- 
quences of  those  first  put  forward  by  Favre  and 
Silbermann,  and  continued  by  Graham,  Deville, 
and  myself. 


<        .1 


CHAPTER  XIII. 

CONCLUSIONS. 

§  90.  The  views  maintained  in  the  preced- 
mg  chapters  as  a  basis  for  a  philosophy  of 
chemistry,  may  be  resumed  as  follows  :_ 

The  chemical  process  may  be  defined  as  the 
integration  or  the  disintegration  of  chemical 
spec.es,  resulting  in  the  production  of  new  spe 
ces,  also  chemical.  Both  of  these  chano-es 
may  be  either  homogeneous  or  heterogeneous  ■ 
that  ,s  to  say,  the  species  concerned  therein 
may  be  elementary,  or,  if  complex,  may  be  lilce 
or  unlike  in  centesimal  composition. 

The  generation,  by  heterogeneous  change  of 
spec.es  dissimilar  to  the  parents  we  have  desig- 
nated  metagenesis.  In  heterogeneous  Integra- 
t.on  two  or  mo.e  unlike  species  combine  to 
form  a  new  one,  and  in  heterogeneous  disinte- 
grat.on  a  species  separates  into  two  or  more 
unUke  to  each  other.  The  union  of  hydrogen 
and  carbon  to  form  acetylene,  of  oxygen  and 

'39 


1 1 


140 


A  Chemical  Philosophy. 


carbon  to  form  carbon  dioxyd,  the  absorption 
of  the  latter  by  sodium  hydrate,  or  of  atmos- 
pheric water  by  calcium  chlorid,  are  examples 
of  heterogeneous  integration.  The  loss  of 
water  in  the  evaporation  of  a  saline  solution,  in 
the  efflorescence  of  hydrated  sodium  carbonate, 
and  the  disengagement  of  carbon  diox3'd  by 
heat  from  calcium  carbonate,  are,  in  like  man- 
ner, examples  of  heterogeneous  disintegration. 
All  solution  is  heterogeneous  integration ; 
while  the  separation  of  crystals  from  a  solu- 
tion is  heterogeneous  disintegration. 

What  is  called  double  decomposition  con- 
sists in  heterogeneous  integration,  followed 
immediately  by  a  disintegration  generating  two 
(or  more)  new  species.  In  other  words,  two 
species  disappear,  and  two  others  take  their 
places  ;  the  double  decomposition  being  the 
result  of  two  consecutive  actions,  and  the  hete- 
rogeneous disintegration  following  so  closely  on 
integration  that  it  is  difficult  or  impossible  to 
arrest  the  change  at  the  end  of  the  first  stage, 
so  as  to  isolate  the  unstable  species  before  it  is 
destroyed.  When  these  processes  are  confined 
within  narrow  limits  of  time  and  temperature, 


Conclusions.  141 

the  hitherto   unexplained   operation   has  been 
called  catalysis,  or  action  by  presence. 

§91-      The     generation,    by     homogeneous 
change,  of    species    like   the  parents   in    cen- 
tesimal composition  we   have  designated  met- 
amorphosis.     In  homogeneous  integration  the 
identity  of  a  species  is  lost  in  that  of  a  new 
one  of  higher  equivalent  weight.     In  homoge- 
neous disintegration   this  process  is  reversed, 
and  a  new  species  is  formed,  having  the  same 
centesimal  composition  but  a  lower  equivalent 
weight.      These  two   cases   of   metamorphosis 
correspond  to  what   are  called  polymerization 
and  depolymerization. 

In  many  instances,  as  in  the  vapors  of  sul- 
phur at  different  temperatures,  and  in  pentene, 
and  the  various  aldehydes  and  their  polymers,' 
the  ratios   between  the  equivalent  weights   of 
the   species    concerned   are   very    simple;    but 
m  other  cases,  as  in  the  polymers  of  many  ele- 
mental species,  such  as  carbon,  tin,  and  phos- 
phorus, in  silicon  dioxyd,  and  in  native  silicates 
and  carbonates,  these  ratios  are  more  complica- 
ted, and  do  not  correspond  to  very  simple  frac 
tions   or   multiples.     Hence   we   infer,  in   the 


tt  i. 


i  ■ 


142 


A  Chemical  Philosophy. 


sill 


process  of  metamorphosis,  a  temporary  homo- 
geneous disintegration  of  the  species  into  more 
elemental  forms,  which,  by  redintegration,  may 
give  rise  to  new  species,  either  of  higher 
or  of  lower  equivalent  weights  than  the  par- 
ent. 

§  92.  Some  species  with  difficulty  assume  or 
maintain  a  polymeric  state,  —  as,  for  example, 
carbon  dioxyd,  which  is  liquid  only  at  very  low 
temperatures,  or  under  great  pressure,  and, 
moreover,  forms  a  very  volatile  and  unstable 
solid ;  while  other  species,  like  carbon  itself, 
silicon,  and  silicon  dioxyd,  are  known  to  us 
only  in  dense  polymeric  forms,  of  great  though 
different  degrees  of  condensation.  Between 
these  two  extremes  are  bodies  which,  like 
phosphorus,  pentine,  and  the  aldehydes,  yield 
various  polymers  of  different  degrees  of  com- 
plexity and  of  stability. 

All  known  liquid  and  solid  species,  whether 
elementary  or  not,  are  polymers  of  some  simpler 
species,  which,  in  very  many  cases,  is  capable 
of  assuming  the  form  of  a  gas  or  vapor.  Such 
vapors  themselves  are  sometimes  polymers 
which,   at    higher    temperatures,   may   be    re- 


Conclusions, 


143 


solved  into  still  simpler  forms  by  homogeneous 
differentiation,  as  in  the  case  of  metaldehyde, 
of  sulphur-vapor  below  500°,  and  of  iodine-vapor 
below   800°.      Theoretically,  we   may  suppose 
that  even  oxygen,  nitrogen,  and  hydrogen  may 
also  undergo  such  resolutions  at  higher  temper- 
atures and  under  diminished  pressure.     There 
are,  however,  many  solid  species  which,  from  the 
facility  with  which  they  undergo  heterogeneous 
differentiation,  or  from    their   high   equivalent 
weights,  cannot  exist  in  the  vaporous  state. 

By   integration,   alike    in    metagenesis    and 
metamorphosis,  we  rise  to  higher  chemical  spe- 
cies, and  by  disintegration  descend  to  simpler 
ones.     If,  as  we  may  suppose,  all  chemical  spe- 
cies  have  come  from   one   primal    matter,    it 
follows  that  the  final  disintegration  of  all 'so- 
called  elementary  species  must  be  a  homogene- 
ous one,  giving  rise  to  that  primal  substance, 
which  can  only  be  conjectured  to  be  a  species 
much  more  attenuated  than  hydrogen,  and  pos- 
sibly identical  with  the  matter  giving  the  green 
line  1474  of  the  corona,  or  some  other  unknown 
solar  element. 

§  93.  The  condensation  of  gases  into  solids 


144 


A  Chemical  Philosophy. 


J 


t 


or  liquids,  and  the  fusion  and  volatilization  of 
these,  when  not  attended  with  heterogeneous 
disintegration,  arc  examples  of  metamorphosis. 
All  such  changes  of  state  —  the  conversion  of 
water  into  steam,  the  condensation  of  this  again 
into  water,  its  conversion  into  ice,  and  the  fusion 
and  evaporation  of  the  latter  —  are,  conse- 
quently, chemical  processes.  The  precise  na- 
ture of  the  liquid  and  of  the  colloid  or  porodic 
state,  as  compared  with  crystalline  individual- 
ized solids,  is  not  yet  clear.  The  passage  from 
the  colloid  to  the  crystalline,  as  well  as  that  from 
the  liquid  to  the  crystalline,  is  generally  at- 
tended with  condensation  ;  while  the  fusion  of  a 
solid  is  a  metamorphosis  by  expansion.  To  this, 
however,  the  conduct  of  water,  and  some  other 
bodies  in  solidification,  offers  an  exception.  The 
same  vaporous  species,  steam,  gives  rise  by 
polymerization  to  the  two  distinct  species, 
water  and  ice,  having  different  equivalent- 
weights.  Analogies  to  this  are  s'  u  j 
different  forms  of  liquid  and  •^''  "  noi  -, 
and  of  tin,  in  the  various  liqu  and  .id  spe- 
cies of  di-pentines  or  turpentine-oils  '>'  ith  differ- 
ent specific  gravities  and  boiling-points,  and  in 


Conclusions.  j^c 

the   isomeric   butylic  alcohols,    as   well   as    in 
native  silicates  and  carbonates.     It  is  probable 
that  the  so-called  isomers  of  other  non-volatile 
bodies,  like  the  different  tartaric  acids,  are  poly- 
mers  similar  in  their  constitution  to  these. 
_  By  polymerization,  or  homogeneous  Integra- 
tion,   the   normal   gaseous   or   volatile   species 
are   thus    changed   into    liquids   and    solids   of 
greater  or  less  degrees  of  condensation.      Of 
these  the  denser,  other  things  being  equal,  are 
the  harder  and  the  more  stable  or  indifferent  to 
chemical  changes  such  as  fusion  and  solution. 
This  relation  has  been  illustrated  at  length  by 
showing  that  the  hardness  and  fixity  of  "native 
sulphids,  oxyds,  carbonates,  and   silicates,  and 
their  resistance  to  the  action  of  solvents,  aug- 
ment  with  the  condensation  of  the  species. 

§  94-  All  chemical  changes  are  subordinated 
to  measure  and  weight,  as  shown  in  the  law  of 
definite   proportions  alike    by  volume   and   by 
weight.     The  law  of  numbers  is  made  evident, 
not  only  in  multiple  proportions,   and  in  met- 
amorphosis,  but    in    homologous    or    progres- 
sive    series,    which,   so    far    from    being ''con- 
fined to  certain  hydrocarbonaceous  species,  are 


146 


A  Chcviical  Philosophy. 


1   ! 
1   i 


;  '!< 


found   throughout  all  classes  of  chemical  com- 
pounds. 

In  the  combination  or  integration  of  gases 
and  vapors  the  volumes  uniting  are  lost  in 
that  of  the  product,  there  being  an  identifica- 
tion of  volume.  The  converse  is  true  in  de- 
composition, or  disintegration,  which  is  differ- 
entiation. The  fact  that  this  law  of  volumes 
is  universal,  and  applies  not  only  to  gases  and 
vapors  but  to  liquids  and  solids,  has  been 
obscured  by  the  false  assumption  that  the  vol- 
ume for  solids  is  a  variable  and  arbitrary  quan- 
tity, conditioned  by  crystalline  form  ;  so  that  no 
constant  comparison  was  possible  between  the 
volume  of  solids  and  that  of  gases.  Moreover, 
there  have  hitherto  been  two  distinct  units  of 
comparison,  the  one  for  gases,  and  the  other 
for  liquids  and  solids.  The  weight  of  a  given 
volume  of  a  gas  or  vapor  as  compared  with  that 
of  the  same  volume  of  hydrogen  gas  at  similar 
temperature  and  pressure,  —  which  is  its  equiv- 
alent weight,  —  is,  at  the  same  time,  its  specific 
gravity,  hydrogen  being  unity.  The  weight  of 
a  similar  volume  of  a  liquid  or  solid  species  is, 
on  the  contrary,  compared  with  that  of  water ; 


I 


Conclusions.      „  j.- 

and  its  equivalent  weight  varies  as  its  specific 
gravity,  tlut  of  ^vater,  wl,icl,  at  its  maximum 
density  is  tl,e  unit,  being  ,628  (H,0)  =  29,.44. 
!>95-   In  order  to  compare  liquids  and  solids 
W'tli  gases  and  vapors,  it  is  necessary  to  refer 
them  to  a  common  standard  of  density,  or,  i„ 
other  wor<ls,  to  determine  the  relation  of  den- 
s^y  between  water  and  hydrogen  gas.     This  is 
the  relation  oid:p  ,n  the  proportion  d  ■./.■■,■„ 

provided  ,.  be  the  density  of  water  at  4-;  and 
/  that  of  hydrof  en  at  0°.     To  fix  this  relation 
we  compare   the  weights   of  a  given   volume 
'one  htre)  of  hydrogen  and  of  steam  at  760  mm 
and  ,00",  with  the  same  volume  of  water  at  the 
same  temperature ;   remembering,   meanwhile, 
that   this   liquid   at   4"  has   a  weight  of    ,000 
grams  to  the  litre.     We  have  thus  the  means 
of  determn,ing  the  specific  gravity  of  hydrogen 
gas,  of  steam,  and  of  water  at  100°,  -the  tem 
perature  of  its  ebullition  and  its  condensation 
at  760  mm.,  _  as  compared  with  water  at  its 
maxmium  density,  which  has  been  assumed  as 
the  unit   of    specific   gravity  for  liquids   and 
solids. 

§  96.  With  gases  and  vapors,  the  equivalent 


148 


A  Chemical  Philosophy. 


i,j4^ 


weights  of  which  are  directly  as  their  densities, 
it  is  evident  that  in  the  proportion  d  :  f  :  \  :  v, 
we  have  d=^p.  But  when  this  formula  is  ap- 
plied to  liquids  and  solids,  while  /  still  repre- 
sents alike  the  equivalent  weight  and  the  den- 
sity (hydrogen  being  unity)  of  the  normal 
gaseous  ;  pecies,  d  is  made  to  represent  the 
density  of  some  polymer  thereof.  In  the  case 
of  water  itself,  where  /=  17.9633,  is  both  the 
equivalent  weight  and  the  density  of  steam, 
HoO  (hydrogen  gas,  H2=  2.0000),  rt' represents 
the  weight  of  that  liquid  at  its  maximum  den- 
sity (which  is  assumed  as  the  unit  of  specific 
gravity).     We  have  then  :  — 


1. 0000  :  17.9633  ::  i 


I7-9633- 


The  number  thus  found  is  the  reciprocal  of 
the  coefHcient  of  the  condensation  suffered  by 
p  in  passing  from  the  gaseous  condition  to  the 
density  in  question.  To  determine  the  amount 
of  this  condensation  we  have  dimply  to  compare 
the  weight  of  equal  volumes  of  the  gaseous  p 
and  the  liquid  d  at  the  same  temperature,  or,  in 
other  ww.^s,  knowing  the  weight  of  a  litre  of 
steam,  HgO,  at  the  standard  pressure,  and  100°, 


Conclusions. 


149 


to  compare  it  with  the  weight  of  a  litre  of  water 
at  1 00°.  In  this  way  we  have  found  that  water 
IS  formed  by  the  condensation  into  one  volume 
of  1628  volumes  of  HoO,  and  consequently  that 
1628X 17-9633  =29,244  =  the  equivalent  weight 
of  water ;  its  specific  gravity  at  100°  being 
0.95878. 

In  the  proportion  d'.pwiw,  as  applied  to 
any  liquid  or  solid  species,  /  does  not  represent 
its  real  rquivalent  weight,  but  the  weight  of 
the  normal  species  which,  by  its  condensation, 
gives  rise  to  the  liquid  or  solid.  The  value  of  v 
is  thus  that  of  the  reciprocal  of  the  coefficient 
of  condensation.  The  equivalent  weight  of 
water  (and  of  any  other  species  having  a  spe- 
cific gravity  of  i.ooo)  being  as  given  above, 
we  have  29,244 -f- 7-  =  the  coefficient  of  con- 
densation. 

From  these  data,  remembering  that  the  law 
of  volumes  is  universal,  and  that  equivalent 
weights  are  but  the  weights  of  equal  volumes, 
it  is  clear  that  the  equivalent  weight  varies 
directly  as  the  specific  gravity ;  so  that,  this 
being  known,  it  is  easy  to  calculate  the  true 
equivalent  weight  of  any  species. 


150 


A  Chemical  Philosophy. 


% 


§  97.  The  phenomena  of  temperature,  radiant 
energy,  and  electricity,  ap^  irent  in  chemical 
changes,  do  not  belong  to  chemism,  but  to 
dynamics.  To  the  dynamical  history  of  species 
pertain  all  questions  as  to  the  atomic  or  molec- 
ular constitution  of  matter,  on  the  one  hand,  or 
its  infinite  divisibility,  on  the  other.  Contin- 
ued subdivisions  cannot  effect  the  destruction 
of  a  chemical  species,  which  is  an  integer  or 
unit,  in  which  the  existence,  as  such,  of  none  of 
the  species  which  may  be  obtained  by  its  disin- 
tegration can  be  affirmed.  No  hypothesis  as 
to  an  atomic  or  molecular  structure,  framed  to 
explain  dynamic  phenomena  in  any  given  spe- 
cies, can,  therefore,  be  legitimately  extended 
to  explain  the  generation  of  those  species 
which  may  be  derived  from  it  either  by  inte- 
gration or  disintegration.  For  these  reasons  it 
is  conceived  that  all  such  hypotheses,  however 
useful  they  may  be  found  in  the  explanation  of 
certain  dynamical  phenomena,  are  foreign  to 
the  domain  <  ^  chemistry,  and  should  hold  no 
place  in  the  theory  of  the  science. 

§  98.  The  chemical  process  is  subordinated 
to  the  influences  of  pressure,  temperature,  and 


Conclusions. 


151 


radiant  energy.     Pressure  influences  chemical 
change,  as  seen  in  its  relations  to  vaporization, 
and  to  heterogeneous  dissociation,  as  well   as 
to  solution  and  to  fusion  ;  all  of  which  it  aids 
or  restrains  according  as  these  are  attended  by 
condensation  or  expansion.     A  remarkable  case 
is  seen  in  its  effect  on  the  brittle  spec^^s  of  tin, 
which,  by  pressure,  undergoes   a   ready  meta- 
morphosis  into   the    denser   species.      In   like 
manner,    as   W.    Spring   has    shown,    ordinary 
phosphorus  is,  by  great  pressure,  changed  into 
one  of  the  denser  red  species  (§§  5,  54).     Hete- 
rogeneous     integration    is    moreover    directly 
effected    thereby,  as    in    Spring's   experiments 
upon  mixtures  of  metals  with  sulphur,  or  with 
each  other. 

Heat  promotes  union  within  certain  limits, 
as  seen  in  the  solution  of  many  substances  in 
water,  and  in  combustion ;  where,  however,  it 
may  act  by  first  causing  dissociation,  since 
nearly  all  species  known  are  disintegrated  at 
sufficiently  high  temperatures,  when  the  ten- 
dency to  integration  is  nullified,  and  matter 
becomes  indifferent  to  chemical  change.  Heat 
is  the  universal  disintegrator;    and  chanoe  of 


152 


A  Chemical  Philosophy. 


state  comes  in  the  primal  matter  by  reduction 
of  temperature,  and  increase  of  pressure,  with 
which  chemical  integration  begins.  Radiant 
energy  also  effects  chemical  change,  as  seen  in 
the  action  of  light ;  and  the  electric  current 
causes  chemical  disintegration,  in  a  way  not  yet 
well  understood. 

Chemism,  however,  is  not  to  be  confounded 
with  any  of  the  dynamic  agencies  just  mentioned. 
It  is  one  of  the  manifestations  of  an  energy  per- 
taining to  matter,  which  inclines  it  to  integra- 
tion or  disintegration,  as  conditions  favor  the 
one  or  the  other  mode  of  change.  The  energy 
thus  displayed  in  change  of  state  appears  also 
in  these  dynamic  activities,  and  is  one  and  the 
same,  whether  manifested  on  the  plane  of  dy- 
namics, on  that  of  chemism,  or  on  the  higher 
plane  of  biotics ;  but  it  is  an  error  to  confound 
either  dynamical  or  biotical  with  chemical 
activity. 


INDEX. 


The  black-faced  figures  in  parenthesis  — thus,  (1)  — alike  in 
the  Index  and  in  the  text,  corresi^ond  to  those  prefixed  on 
pages  1-5  to  the  titles  there  numbered  1-17,  which  are  printed 
below  in  capitals. 

Acetylene,  formation  of,  139 

Acids,  inorganic,  complex,  49;  fatty,  vapor-density  of,  122,  note 

Action  by  presence,  14,  141 

Alcohol,  butylic,  isomers  of,  91,  145;  vinic,  diffusion  of,  132 

Aldehyde,  acetic,  S3;   polymers  of,  S9,  105,  141;   formic,  84; 

polymer  of,  ibid. 
Allotropism  as  polymerism,  11 
Alumina,  unit-weight  of,  82;  density  of,  119 
Amphibole,  47,  57,  58 
Andrews,  Thomas,  on  vapors,  90 
Aniline  compounds,  their  equivalent  weights,  48 
Anisomeric  homologues,  45 

Anomalies  in  Atomic  Volume,  etc.  (1),  noted,  i ;  cited,  u 
Aragonite,  53,  93;  density  of,  105;  formula  of,  ibid. 
Armstrong  and  Tilden  on  turpentine-oils,  87,  note 
Arsenious  oxyd,  122,  tiote 
Atmosphere,  The  Chemical  and  Geological  Relations 

OF  (13),  noted,  4;  cited,  34 
Atmosphere,  part  of  the  interstellar  medium,  ^^ 

153 


I 


I 


154 


A  CJicmical  PJiilosophy. 


'ft 


Atomic  hypothesis,  history  of,  60  et  seq.;  Dalton  on,  60,  62, 67  ; 
Brodie  on,  67 ;  Wright,  C.  R.  A.,  on,  67,  note  ;  Stallo  on, 
62,  note;  Whevvell  on,  61,  note;  in  chemistry,  62,  65,  66, 
115,  118,  123,  150;  volumes,  see  Molecular  volumes 

Benzoic  acid,  its  solubility,  116 

Bernoulli,  kinetic  theory  of  gases,  61 

Biotics  definccl,  18,  19;  relations  of,  21,  152 

Boiling  point  of  liquids,  40 

Breithaupt,  A.,  porodic  bodies,   54,  note,   132;    carbon-spars, 

103 
Brodie,  Benjamin,  Calculus,  26,  27;  Ideal  Chemistry,  29,  31; 

ideal  elements,  26,  29,  30 ;  atomic  hypothesis,  67 
Bromine,  its  change  by  heat,  94,  122,  note 
Butane,  its  equivalent  weight,  no 
Butylic  alcohol,  isomers,  91,  145 

Cagniard  de  la  Tour  on  dense  vapors,  90 

Calcite,  supposed  molecular  structure,  66;  densities,  53,  loi, 

\Oi,etseq.;  species  of,  104;  formulas  of,  106 
Camphenes,  80,  96 
Carbon,  chemistry  of,  44;  series,  44,  49;  polymers  of,  12,42, 

141,  142;    carbon  dioxyd,  polymers  of,  97,    107,    142; 

spars,  see  Calcite 
Carbonitcs,  the  genus,  103 
Catalysis  defined,  14,  141 
Celestial  Ciiemistuv  from  the  Time  of  Newton  (15), 

noted,  4 ;  cited,  26-35 
Changes  of  state,  chemical,  75,  135,  136,  144 
Charcoal,  an  anhydrid,  12 
Chemical  activities  confounded  with  dynamics,  19-21,  65,  150, 

152;  change  related  to  pressure,  151  ;  elements,  origin  of, 

9,  23  et  seq.,  37,43,  94;  indifference  related  to  equivalent 

weight,  51  et  seq.,  59,  88,  99,  118  et  seq.,  145;  molecules, 

6},,  114;  process,  nature  of,  7  et  seq.,  22,80,  139;  species, 

integral,  15,  17,  22,  62,  66,  150 
Chemical  Changes,  On  vwv.  Theory  of,  etc.  (4),  noted,  2; 

cited,  7-10,  15,  22,  3S-40,  44,  62,  66,  68,  70,  Ti 


/ 


Index, 


155 


Chemical  Classification,  On  Some  rRmcirLEs  to  be 
Considered  in  (2),  noted,  i;  cited,  n,  12 
Remarks  on   (1).    See  Anomalies  in   Atomic  Vol- 

UME,  lie. 

Chemical  Homologies.  Illustrations  of  (6),  noted    v 
cited,  47,  106.  ^    ^'  •  ^' 

Chemistry.  Celestial,  from  the  Time  of  Newton  (15) 
^ee  Celestial  Chemistry,  etc 
of  Primeval  Earth  ( 1 1 ),  noted,  4 ;  cited,  26,  28 
Law  of  Volumes  in  (17).  noted,  5;  cited,  62-64,  78 
Theoretical,  A  Century's  Progress  in  (12),  notU4; 
cited  17,22,24-26,31-33  '^' 

rehuion   of  to  dynamics,  20.  21,  65.  152 ;   to  biotics.  ar. 

Chloral,  its  polymerization,  84 

Chlorids  in  aqueous  solution,  22;  as  normal  species,  119 

Chlorine,  its  change  by  heat,  94,  ,22,  note 

Chlorhydric  acid,  genesis  of.  9;   H.  Wurtz  on  its  volume, 

Chrysolite,  56,  58 

Clarke,  F.  W.,  celestial  chemistry,  31,  35 

Clifford,  W.  K.,  chemistry  and  dynamics,  20 

Cobaltic  ammonia  salts,  48,  79 

Coefficient  of  condensation,  64,  loS,  120,  148 

Cold,  action  of  on  tin,  92 ;  on  iron,  93 

Colloids,  their  nature,  116,  132;  identical  with  porodic  bodies, 

133;  their  significance  in  mineralogy,  54;  action  of  fluor- 

hydric  acid  on,  58,  59 

Colophene,  86-88,  96 

Combination,  chemical,  Deville  on,  136 

Complex  inorganic  acids  of  Gibbs,  49 

Condensation,  related  to  hardness,  51,  52  et  se<j.,  88,  97,  nS 

145 ;  to  chemical  indifference,  52,  59,88.  145;  in  liquid 

species,  40;  heat  evolved  in,  87,88 
Cooke,  J.  v.,  on  equivalent  weights.  26 
Corona,  the  solar,  32,  i-],  143 
Cosmogony,  23,  :ioie,  24 
Cowles's  electric  furnace,  97,  note      —     -  -- 


i 


^1 


156 


A  Clicmical  Philosophy. 


Crafts,  J.  M.,  action  of  heat  on  iodine,  94 
Crookes,  W.,  genesis  of  elements,  36,  yj 
Cryohyclrates,  Guthrie  on,  115 

Crystalline  individuality,  17,  18,  39;  form  as  related  to  vol- 
ume, 71,72  '^^  ■'''"?•'  m6 
Crystallization  from  solutions,  140 
Cyanite,  52 


w 


V    I 


i 


Hi -J 


Dalton,  J.,  adopts  atomic  hypothesis,  61,  62,  67,  68 

Datolite,  chemical  indifference  of,  57 

Daubeny,  C,  the  atomic  hypothesis,  61,  note,  69,  note 

Decomposition,  double,  9,  13,  14,  98,  140 

Deliquescence,  133 

Density,  of  solids,  relation  to  equivalent  weight,  12,  38,  39,  41, 
47-49;  a  function  thereof,  118,  120,  149;  of  water, 
steam,  and  hydrogen,  76-78,  147 ;  change  of,  its  signifi- 
cance, 125;  variations  of  in  related  solids,  102;  relation 
of  to  temperature,  no;  law  of,  loo,  103;  units  of  for 
gases  and  solids,  107,  108,    -^6 

Depolymerization,  81,  141 

Deville.    See  Sainte-Claire  Deville,  H. 

Diethylamine,  115 

Differentiation,  chemical,  14,  16,  81,  86 

Diffusion,  liquid,  Graham  on,  75,  129-135;  gaseous,  128,  129, 
136;  chemical  relations  of,  128,  135;  applied  to  chemical 
analysis,  131 ;  compared  to  volatilization,  128, 131 ;  mole- 
cules of  Graham,  130 

Di-pentine,  87 

Dipyre,  53 

Disintegration,  chemical,  17,  80 

Disintegrator,  heat  the  universal,  151 

Dissociation,  chemical,  a  universal  law,  28  et  seq.,  35,  94,  151; 
celestial,  27,  28,  32,  143;  compared  to  vaporization, 
128,  134-136;  Sainte-Claire  Deville  on,  27,  28,  138 
et  seq. 

Di-turpene,  86 

Dobereiner  on  chemical  triads,  24 

Drion  on  dense  vapors,  90 


157 


on 


Index, 

Dumas,  J.  B.,  origin  of   elements,  24-26,  32  et  scq.,  35; 

atomic  volumes,  71,  73;  conferences  with,  73 
Dynamics,  relation  of  to  chemistry,  19  d  seq.,  65,  150,  152 

Earth,  Chemistry  of  the  Primeval  (11).  See  Chemis- 
try OK  THE  Primeval  Earth 

Efflorescence,  133 

Electricity,  95,  98,  note;  in  chemical  changes,  152 

Elements,  chemical.     See  Chemical  elements 

Energy  in  nature,  21,  152 

Epidote,  56 

Equivalent  Volumes,  On,  etc.  (4).  See  Chemical 
Changes,  On  the  Theory  of;  also.  Mineral  Spe- 
cies, ETC. 

Equivalent  weights,  elevated,  47-49,  79,  „2;  of  carbon-spars, 
47,  loi  et  seq.;  of  feldspars,  47;  of  pvroxcnes,  ibid.;  of 
water  and  ice,  78,  109,  149.    See  Density,  etc. 

Euphotide  and  saussurite,  on,  51 

Eutectic  bodies,  116 

Eutexia,  Guthrie  on,  116,  note 

Evaporation,  related  to  diffusion,  128,  131,  133,  137;  a  chemi- 
cal  process,  137,  138,  140,  144 


Faraday  on  chemistry  and  dynamics,  20 

Fatty  acids,  vapor-density  of,  122,  note 

Favre  and  Silbermann,  thermo-chemistry,  39,  113;   chemical 

changes,  133,  137 
Faye's  solar  hypothesis,  27 
Feldspars,  47,  56,  58 

Formulas,  structural,  in  chemistry,  15,  45,  (^-j^  note,  97 
Fouque,  fluorhydric  acid  on  silicates,  56 
Fusibility  related  to  condensation,  119,  145 

Ganot,  Elements  de  Physique,  76 

Garnet,  56 

G-ses,  densities  of,  related  to  solids,  38,  70,  107,  no,  147,  149; 

unit  of  density  for,  107,   146;  law  of  diffusion  of,  129; 

Kinetic  theory  of,  61.    See  Normal  or  gaseous  species 


158 


A  Chemical  PJiilosophy. 


Gaudin,  crystalline  molecules,  i6 

Gay  Lussac,  law  of  volumes,  69 

Gems,  order  of,  54 

Genealogy,  chemical,  9,  15,  97 

Genesis  of  chemical  elements.  Sec  Chemical  elements,  origin 
of 

Gcogeny,  19,  note,  23,  note 

Gerhardt,  Ch.,  on  progressive  series,  43;  on  structural  formu- 
las, 45 

Gibbs,  Wolcott,  on  polytungstates,  48 ;  complex  inorganic 
acids,  49 

Gmelin,  L.,  on  volumes,  71 ;  condensation  of  oxyds,  88 

Graham,  Thomas,  on  liquid  diffusion,  75,  12S,  133;  relations 
of  to  volatilization,  137;  colloids,  132;  polymerization 
in  solution,  129-131;  conferences  with,  13S 

Guthrie,  Fred.,  cryohydrates,  115;  physical  molecules,  1 1 5-1 18 ; 
eutexia,  iiS 

Gypsum,  98  . , 


V 


?'5 


Halloysite,  58 

Hardness,  its  relation   to  condensation,   51,  52,  88,  97,   118, 

MS 

Heat,  its  relation  to  chemical  changes,  136,  151;  evolved  in 
polymerization,  87  d  scq. 

Hegel  on  chemical  change,  16,  17 

Helium,  a  supposed  solar  element,  37 

Helmholtz  on  chemistry  and  dynamics,  20 

Henry,  Louis,  on  polymerization,  118  d  scq. 

Heptine,  86 

Herepath,  J.,  kinetic  theory  of  gases,  62 

Heptine,  86 

Hinrichs,  G.,  on  primary  matter,  t^-}^,  note        > 

Holoedrites,  the  genus,  105 

Homogeneous  chemical  species.  Sec  Chemical  species,  inte- 
gral 

Homologous  series,  history  of,  43,  44,  49,  145 ;  their  universal- 
ity, 44,  49,  145 

Homologues,  anisomeric,  45;  isomeric,  ibid. 


Index.  j-g 

Hornblende,  52,  53 
Huggins  on  eloniental  matter,  ^i,  note 
Hydrofluoric  acid,  action  of  on  silicates,  C6-CQ 
Hylogeny,  23,  note  ^ 

Ice.  its  density,  78 ;  relation  to  water,  91.  144 
Identification,  chemical,  14,  16,  146 

Jollie.'sf  "'''""'"■^'^°'''  ^^  ^^"-'^  94,  122,  note,  143 

Insolubility  related  to  condensation.    ^..Condensation  related 

to  chemical  indifference 
Integration,  chemical,  ,7,  139./ ,.5,.,  ,43,  ,3 
Intcrpenetration  in  chemistry,  15,  16 
Iron,  supposed  effect  of  cold  on,  93 
Isomorphism,  relation  to  volume,  71-73,  146 
Isomeric  homologues,  45 
Isoprene,  86,  96 

]^Zl  "  """'  ™  '^''  ""'"■  '  ■  ""'•  5-  53 

Kant,  Em.,  on  chemical  union,  15  et  sea. 

Kinetic  theory  of  gases,  6i 

Kirchhoff,  G.,  on  spectral  lines,  37,  95 

Kopp,  H.,  atomic  volume,  72;  density  of  water,  77 

Lavoisier  on  primal  matter,  23,  35 
Leroyer,  atomic  volumes,  71 
Leucite,  58 

Light  in  chemical  change,  152 
Limonenes,  85,  96 

Liquids   as  polyrners,  41,  48,  143;  determination  of  densities 

or,  40;  dmusion  in,  1-9-131 
Lockyer,  N.,  solar  physics,  29,  32 

Mackintosh.  J.  B.,  action  of  fluorhydric  acid  on  silicates,  56 
Macvicar,  J.  G.,  on  crystalline  molecules,  16 


i! 


i6o 


A   CJicrnical  Philosophy. 


II 


■5||! 


'.i 


•\    ..1 


i 


I; 


Magnesian  phosphate,  88,  98 

Materia  prima,  17,  23,  n,  note,  36,  95,  143 

Mathesis,  23,  ;/<)/<' 

Matter,  divisibility  cf,  60 

Meionite,  51,  52,  w^te 

Metachlorai,  84 

Metagenesis  in  chemistry,  8,  15,  45,  80,  97,  139,  143 

Metaturpene,  88 

Metaldchyde,  84,  89,  121,  note 

Methylene  oxyd,  84,  12  v,  note 

Metamorphosis  in  chemistry,  8,  14,  80  et  scq.,  141,  142;  by  ex- 
pansion, 9,  Si  ;  by  condensation,  10,  Si 

Metallatcs,  55 

Metallometallates,  55 

Metallic  oxyds  as  polymers,  55,  88,  97,  98,  119,  121,  note 

Meyer,  Victor,  action  of  heat  on  chlorine,  99 

Micas,  58 

Micaceous  type  in  mineralogy,  54 

Mills,  E.  J.,  genesis  of  elements,  36 

Mineral  Species,  On  the  Constitution  and  Equiva- 
lent Volume  ok  Some  (5),  noted,  2;  cited,  45,  47, 
62,  70 

Mineralogy,  A  Natural  System  of,  etc.  (16),  noted,  5; 
cited,  55,  57,  64,  65,  79,  So,  82,  127 

Mineralogy  defined,  iS 

Miner/vLogy,  OiijKCTS  AND  METHODS  OF  (10),  noted,  3; 
cited,  i6,  17,  41,  42,  47,  53,  68,  74,  117,  138 

Mitscherlich,  isomorphous  groups,  72 

Molecular  hypothesis.     See  Atomic  hypothesis 

Molecular  volume,  63,  65,  124 

Molecules,  G3;  physical,  63,  114;  chemical,  63,  114;  diffusion, 
Graham  on,  130 

Mono-pcntme,  88 

Nascen'  ?tate  of  bodies,  98 

Nati  iE  IN  Thought  and  Language  (14),  noted,  4;  cited, 

14,  18,  19,  20,  21,  2.1,  44 
N'lbulae,  chemistry  of,  33-35 ;  possible  origin  of,  2,^ 


Index. 


i6i 


Newton,  Celestial  Chemistry  from  the  Time  of  (15) 

noted,  4 ;  cited,  26-35 
Newton  on  atomic  hypothesis,  69;  his  theory  of  hght,  Cn 
Nitric  tetroxvd,  122,  note  ' 

Normal  or  gaseous  species,  90,  91.  94,  97-99,  107,  119,  i=x.  note, 

M2,  145,  148,  149 
Numbers  in  chemistry,  law  of,  43  ct  scq.,  69,  145 

Ocean,  part  of  interstellar  medium,  ^ 

Oken,  Lorcnz,  23;  his  Physiophilosophy,  23,  note 

Umnia  mensura  et  numero,  etc.,  69,  note 

Ontology,  23,  note 

Opal,  53,  58 

Osmic  oxyd,  121,  note 

Otto  on  atomic  volume,  71 

Oxygen,  its  combining  weight,  77,  100,  ro2,  108 

Oxyds  anhydrous,  in  mineralogy,  55;  solid,  as  polymers,   cc. 

88,  98,  119,  122.  note;  classification  of,  121.  note 
Ozone,  II,  93 

Paraldehyde,  83,  84,  89,  122,  note 

Pontine,  86  et  scq.  ■  polymers  of,  87,  89-91,  96 

Periodic  law,  46  ^  ^     -y 

Petal ite,  56,  58 

Pettenkofer,  chemical  elements,  24,  y 

Phosphorus,  polymers  of,  12,  42,  91.  126,  141,  142,  ici 

1  hylloid  type  in  mineralogy,  54 

PHYsioLor.v,  The  Domun  of,  etc.  (14).    See  Nature  in 

THOUr.HT  AND   LANGUAGE 

Physiology,  general,  19,  note;  mineral,  ibid. 
Pickering,  Spencer,  physical  molecules,  iij,  n;    m 
Pinenes,  85,  96  "^ 

Pneumatogcny,  23,  note 
Polycarbonates,  47,  49,  104-106 

Polymerism  defined  and  illustrated.  10-12,  53,  ,,4.  ,^5  ;  j,  ,„ts, 
39,  40;  m  non-gaseous  species,  41,42,  145;  in  solids  and 


■r 


i^ 


162 


A  Chemical  Philosophy, 


liquids,  48,  142;  in  water  and  ice,  40,  75,  76,  82,  91,  108, 
13S,  144,  147,  148;  pentine,  87,  88,89,91,96;  aldehydes, 
83,  84;  of  butylic  alcohol,  91,  145;  of  various  precipi- 
tates, 98;  of  oxyds,  phosphates,  and  silicates  by  heat, 
88;  in  solutions,  Graham  on,  130,  131  ;  coefficient  of,  see 
Coefficient  of  condensation ;  relation  to  hardness,  see 
Hardness  in  relation  to  condensation ;  to  chemical  in- 
difference, see  Chemical  indifference ;  to  specific  gravity 
of  solids,  see  Density  in  relation  to  equivalent  weight 

Polymolybdates,  49 

Polyphosphates,  49 

Polysilicates,  47,  49,  118 

Polytungstates,  48,  79 

Polyturpenes,  86 

Polyvanadates,  49 

Porodini  of  IJreithaupt,  54 

Porodic  type  in  mineralogy,  54,  58,  59,  132;  see  Colloids 

Pressure,  relation  to  chemical  change,  151 

Primal  matter.     See  Materia  prima 

Priestley,  J.,  discourse  at  grave  of.  See  Chemistry,  Theo- 
retical, A  Century's  Progress  in  (13) 

Process,  The  Ciiemical,  Thoughts  on  (7),  noted,  3;  cited, 
14,  16,  22;  nature  of  defined,  7-22,  139 

Prout's  hypothesis,  25,  46 

Progressive  scries  in  chemistry,  43-45,  48,  145 

Pyrognomic  minerals,  88 

Pyroxene,  47,  52,  57 

Quartz,  53,  58,  107 

Reciprocal  number,  of  species,  no;  of  coefficient  of  conden- 
sation, 64,  loS,  no,  14S,  149 
Rcgnault,  V.,  weight  of  hydrogen,  76 
Richards,  R.  II.,  metamorphosis  of  tin,  92 

Ralnte-Claire  Devllle,  H.,  on  dissociation,  27,  28,  133-136, 

138;  conferences  with,  137 
Saussurite.    See  Euphotide 


Index. 


163 


Scheerer,  Th,  on  pyrognomic  minerals,  88 
^chiel,  James,  on  progressive  series,  43 

Sciences,  natural,  tabular  vievv  of.  19,  „^^, 
besquiturpenes,  86  "  ' 

Shenstone.    ^^^  Tilden  and  Shenstone 
Silbermann.    ^  Favre  and  Silbermann 

Silicates,  tribes  of,  57,  58 

Silicon,  series  of  in  chemistrv  aa   ^,^     r        1 

Q7    in,    ,'*'>' 44.49;  clioxyd,polymerism  of, 
97,  107,  119,  1.2,  note,  142;  unit-weight  for,  82 ;  reduc 
tion  and  volatility  of,  98,  note 
Sillimanite,  52 

Silver  nitrate,  solubility  of,  ri6 
Sodium  chlorid,  11.  Wurtz  on,  126 

Solubility,  of  oxyd  compounds,  99;  at  high  temperatures.  it6- 

t    geo  ogical  relations,  1x7;  relation  of  to  condensation 

145-    •'^'V  Chemical  indifference,  etc 

Solution  ano  the  Chkmical  Pkocess.  Thoughts  on  (7). 

noted,  3;  cited,  14,  16,  22  '' 

Solution  defined  as  chemical,  22,  1:2.  ,4.;  as  heterogeneous 

integration,  140;  densities  of  Graham,  129 
Sohds  density  of  as  related  to  gases,  38,  41.  64.  70,  8:.  91,  107. 
loS,  1:9,  120,  r47_,49.  unit  of  density  for,  146;  as  poly- 
mers,  see  Tolymerism  ^    ^ 

Spar,  order  of,  54 
Spathoid  type  in  mineralogy,  54 
Spathometallates,  55 
Specific  gravity.    ^-^-^  Density 
Spodumene,  56 

Spring,  W.,  chemical  effects  of  pressure,  ret 
btallo  on  atomic  hypothesis,  62,  nott 
Staurolite,  56 

Steam    its  weight   7fW8,  ,09;   conversion  into  water.  75-78. 
loS,  109,  138-144  »  /i  /o» 

Stellar  matter,  chemistry  of,  28,  31,  36,  37,  94 
Stoney,  Geo.  Johnstone,  on  solar  chemistry,  r 
Stoichiogeny,  23,  w/^,  24,  26,  31 


1 64 


A  Chemical  Philosophy. 


I 


Strontian  sulphate,  g8 

Strii^(.L..al  formulas  in  chemistry,  15,  45,  67,  note,  97 
Sulphur-vapor,  density  of,  10,  89,  96,  141,  143 
Sulphur  dioxyd,  93,  121,  note 

Temperature,  relation  to  chemical  change,  150 
Tetra-pentine,  88 

Tilden.     See  Armstrong  and  Tilden 
Tilden  and  Shenstone,  solution  at  high  temperatures,  116 
Tin,  metamorphoses  of,  92,  141,  151 
Tourmaline,  49,  57 
Tridymite,  58,  107 
Tribes  in  mineralogy,  57 
Tri-pentine,  87 

Tschermak  on  crystalline  admixtures,  107 
Turpentine-oils,  85  et  seq.,  89 

Turpene,  its  liquid  and  solid  polymers,  85-87,  90,  91 
Tyndall,  J.,  on  potency  in  matter,  21 

Types  in  Chemistry,  Theory  ok  (8),  noted,  3;  cited,  14, 15; 
their  significance,  1 5,  45,  97 ;  in  mineralogy,  54 

Unit  -weights,  79,  82;  unit  volumes,  79,  83;  of  density  for 
solids  and  liquids,  108,  146;  for  gases,  107,  146 

Valarylene,  86 

Vapors,  dense,  under  pressure,  90;  density  of  as  related  to 
solids,  see  Solids,  density  of 

Vita!  phenomena,  18 

Volatilization,  related  to  diffusion,  131,  137  ,  compared  to  de- 
composition, 134.     See  Evaporation 

Volumes,  Law  of  in  Chemistry  (17),  noted,  5;  cited, 
62-64,  78 

Volumes,  significance  of,  71,  79;  relation  to  atomic  hypothesis, 
62,  68;  to  crystalline  form,  71-74,  146;  law  of,  universal, 
68,  70,  71,  75,  79,  146 


Wallach  on  turpentine-oils,  87 

Walteishausen,  Von,  r,    ':r"stalline  admixtures,  106 


Index. 


165 


Water,  equivalent  weight  of,  78, 100;  its  conversion  into  steam, 
75.  n^  78;  lieterogeneous  dissociation  of,  89,  133;  its 
solvent  powers  at  high  temperatures,  ii6j  in  flised 
rocks,  117 

Whewell.  W.,  atomic  hypothesis,  61,  note 
Willemite,  58 

Wright,  C.  R.  A.,  on  atomic  hypothesis,  67,  note 
Wurtz,  Ad.,  on  polysilicates,  118 

Wurtz Henry,  geometrical  chemistry.  122;  on  significance  of 
density,  123;  his  scheme  examined,  124-127 

Zircons,  varying  density  of,  53;  insolubility  of,  56 
Zoisite  compared  with  meionite,  51,  52 


^res3  of 

36frhritk  iC-  <9mHh, 

Boston. 


